Management of croup

INTRODUCTION — Croup (laryngotracheitis) is a respiratory illness characterized by inspiratory stridor, barking cough, and hoarseness. It typically occurs in young children (typically between ages six months to three years) and is chiefly caused by parainfluenza virus. (See "Croup: Clinical features, evaluation, and diagnosis".)

Most children with croup who seek medical attention have a mild, self-limited illness and can be successfully managed as outpatients. The clinician must be able to identify children with mild symptoms, who can be safely managed at home, and those with moderate to severe croup or rapidly progressing symptoms, who require full evaluation and possible treatment in the office or emergency department (ED) setting. (See 'Severity assessment' below and 'Outpatient treatment' below.)

There is no definitive treatment for the viruses that cause croup. Pharmacologic therapy is directed toward decreasing airway edema, and supportive care is directed toward the provision of respiratory support and the maintenance of hydration. Corticosteroids and nebulized epinephrine are the cornerstones of therapy. (See 'Initial treatment' below.)

The approach to the management of croup will be discussed below. The clinical features, evaluation, and diagnosis of croup are discussed separately. (See "Croup: Clinical features, evaluation, and diagnosis".)

SEVERITY ASSESSMENT — This initial step in the management of a child with croup is assessing severity of illness. The first contact with the health care system may occur by phone, and the health care provider must be able to distinguish children with more severe symptoms who need immediate medical attention from those who can be managed at home. (See 'Telephone triage' below.)

When the child is seen in the office or emergency department (ED), croup severity is assessed by examining the child and using a clinical scoring system. (See 'Croup severity score' below.)

Telephone triage — When assessing patients by phone, the health care provider must distinguish children who need immediate medical attention or further evaluation from those who can be managed at home. Children who need further evaluation include those who have:

●Stridor at rest

●Rapid progression of symptoms (ie, symptoms of upper airway obstruction after less than 12 hours of illness)

●Inability to tolerate oral fluids

●Underlying known airway abnormality (eg, subglottic stenosis, subglottic hemangioma, previous intubation)

●Previous episodes of moderate to severe croup

●Medical conditions that predispose to respiratory failure (eg, neuromuscular disorders or bronchopulmonary dysplasia)

●Parental concern that cannot be relieved by reassurance

●Prolonged symptoms (more than three to seven days) or an atypical course (perhaps indicating an alternative diagnosis) (see "Croup: Clinical features, evaluation, and diagnosis", section on 'Differential diagnosis')

Patients who are assessed by phone and are determined to have mild symptoms and none of the above indications for further evaluation can be managed at home. (See 'Home treatment' below.)

Croup severity score — There are a number of validated croup scoring systems. The Westley croup score has been the most extensively studied (table 1) (calculator 1) [1]. Severity is determined by the presence or absence of stridor at rest, degree of chest wall retractions, air entry, presence or absence of pallor or cyanosis, and mental status. In a study that evaluated the individual components of the Westley croup score, the degree of chest wall retractions and air entry were the strongest predictors of need for hospitalization [2].

●Mild croup (Westley croup score of ≤2) – Children with mild croup have no stridor at rest (although stridor may be present when upset or crying), a barking cough, hoarse cry, and either no or only mild chest wall/subcostal retractions [3-5]. (See 'Mild croup' below.)

●Moderate croup (Westley croup score of 3 to 7) – Children with moderate croup have stridor at rest, have at least mild retractions, and may have other symptoms or signs of respiratory distress, but little or no agitation [3-5]. (See 'Moderate to severe croup' below.)

●Severe croup (Westley croup score of ≥8) – Children with severe croup have stridor at rest, although the loudness of the stridor may decrease with worsening upper airway obstruction and decreased air entry [3-5]. Retractions are severe (including indrawing of the sternum), and the child may appear anxious, agitated, or pale and fatigued. Prompt recognition and treatment of children with severe croup are paramount. (See 'Moderate to severe croup' below.)

●Impending respiratory failure (Westley croup score of ≥12) – Croup occasionally results in severe upper airway obstruction with impending respiratory failure, heralded by the following signs [3,5]:

•Fatigue and listlessness

•Marked retractions (although retractions may decrease with increased obstruction and decreased air entry)

•Decreased or absent breath sounds

•Depressed level of consciousness

•Tachycardia out of proportion to fever

•Cyanosis or pallor

Patients who present to an office clinic with severe croup or signs and symptoms of impending respiratory failure should be transported via emergency medical services to an ED for management. (See 'Moderate to severe croup' below.)

Croup clinical scores are widely used in clinical practice and in studies evaluating the efficacy of different treatments for croup. However, it is important to understand that these scores are somewhat subjective and there can be substantial interobserver variability [6,7]. Alternative objective methods have been proposed as potentially more reliable measures of croup severity (eg, methods for quantitatively measuring pulsus paradoxus) [8,9]. Additional data are needed to validate these quantitative methods and demonstrate that they perform better than croup scores before they can replace them in clinical practice. In the meantime, the Westley croup score remains a useful guide for assessing severity of illness and responses to therapies.

MILD CROUP — Children with mild symptoms (Westley croup score of ≤2 (table 1) (calculator 1)) should be treated symptomatically with humidity, fever reduction, and oral fluids. Many such children can be managed by phone, provided that none of the criteria for further evaluation described above are present. (See 'Telephone triage' above.)

Home treatment — The caregivers of children with mild croup who are managed at home should be instructed in provision of supportive care, including mist, antipyretics, and encouragement of fluid intake.

Caregivers may try sitting with the child in a bathroom filled with steam generated by running hot water from the shower to improve symptoms. This may help reassure parents that "something" is being done to reverse the symptoms, and anecdotal evidence supports some benefit with this measure.

Exposure to cold night air also may lessen symptoms of mild croup, although this has never been systematically studied. If parents or caregivers wish to use humidifiers at home, only those that produce mist at room temperature should be used to avoid the risk of burns from steam or the heating element.

Instructions should be provided to the caregivers regarding when to seek medical attention, including watching for [3]:

●Stridor at rest

●Difficulty breathing

●Pallor or cyanosis

●Severe coughing spells

●Drooling or difficulty swallowing

●Fatigue

●Worsening course

●Fever (>38.5°C)

●Prolonged symptoms (longer than seven days)

●Suprasternal retractions

Caregivers also should be provided with guidance regarding when it is safe for them to drive the child to the emergency department (ED) and when they should activate emergency medical services. Transportation by emergency medical services is appropriate for children who are severely agitated, pale or cyanotic, struggling to breathe, or lethargic [3].

Patients who are managed at home should receive a follow-up phone call within 24 hours.

Outpatient treatment — For children with mild croup who are seen in the outpatient setting, we suggest a single dose of oral dexamethasone (0.15 to 0.6 mg/kg, maximum dose 16 mg) or oral prednisolone (1 mg/kg) (algorithm 1). Randomized controlled trials in children with mild croup have demonstrated that treatment with a single dose of oral glucocorticoid reduces the need for reevaluation and shortens the duration of symptoms [10]. (See 'Glucocorticoids' below.)

An alternative approach is nonpharmacologic management with anticipatory guidance about potential worsening and instructions on when to seek care or return for follow-up.

Treatment with nebulized epinephrine is not typically necessary for management of mild croup.

Children with mild croup who are tolerating fluids and have not received nebulized epinephrine can be sent home after specific follow-up (which may occur by phone) has been arranged and the caregiver has received instructions regarding home care and indications to seek medical attention, as described above. (See 'Home treatment' above.)

MODERATE TO SEVERE CROUP

Setting and pace of treatment — The appropriate treatment setting depends upon the severity of symptoms:

●Children with moderate croup (Westley croup score 3 to 7; stridor at rest and mild to moderate retractions but no or little distress or agitation (table 1) (calculator 1)) should be evaluated in the emergency department (ED) or office (provided that the office is equipped to handle acute upper airway obstruction).

●Children with severe croup (Westley croup score ≥8; stridor at rest and marked retractions with agitation, lethargy, or cyanosis (table 1) (calculator 1)) should be evaluated in the ED as they require aggressive therapy, monitoring, and supportive care.

The child with severe croup must be approached cautiously as any increase in anxiety may worsen airway obstruction. The parent or caregiver should be instructed to hold and comfort the child. Nebulized epinephrine should be added as quickly as possible, as described below. In the meantime, health care providers should continuously observe the child and be prepared to provide bag-mask ventilation and advanced airway techniques if the condition worsens (algorithm 1). (See 'Initial treatment' below and 'Respiratory care' below.)

Initial treatment — Initial treatment of moderate to severe croup includes all of the following:

●Dexamethasone – We recommend glucocorticoid therapy for all children with moderate to severe croup. Dexamethasone (0.6 mg/kg, maximum of 16 mg) is generally the preferred glucocorticoid in this setting. Dexamethasone should be administered by the least invasive route possible: oral if oral intake is tolerated, intravenous (IV) if IV access has been established, or intramuscular (IM) if oral intake is not tolerated and IV access has not been established. The oral preparation of dexamethasone (1 mg/mL) has an unpleasant taste. The IV preparation is more concentrated (4 mg per mL) and can be given orally mixed with syrup [3,11]. A single dose of nebulized budesonide (2 mg [2 mL solution] via nebulizer) is an alternative option, particularly for children who are vomiting and who lack IV access [3,5,12]. (See 'Glucocorticoids' below.)

●Nebulized epinephrine – We recommend nebulized epinephrine in all patients with moderate to severe croup. Dosing and administration are as follows (see 'Nebulized epinephrine' below):

•Racemic epinephrine is administered as 0.05 mL/kg per dose (maximum of 0.5 mL) of a 2.25% solution diluted to 3 mL total volume with normal saline. It is given via nebulizer over 15 minutes.

•L-epinephrine (parenteral product) is administered as 0.5 mL/kg per dose (maximum of 5 mL) using the 1 mg/mL strength (may also be referred to as a 1:1000 dilution). It is given via nebulizer over 15 minutes.

●Supportive care, including humidified air or oxygen, antipyretics, and encouragement of fluid intake. (See 'Supportive care' below.)

Observation and disposition — Patients should be observed for three to four hours after initial treatment. The need for additional intervention and/or admission to the hospital is determined chiefly by the response to therapy with corticosteroids and nebulized epinephrine. The majority of children with moderate croup have symptomatic improvement after treatment with nebulized epinephrine and corticosteroids and can be discharged home, whereas those with severe symptoms on presentation are more likely to require hospitalization.

Discharge to home — Patients who have a good response to initial treatment should be observed for three to four hours after pharmacologic intervention (algorithm 1) [13-16]. Croup symptoms usually improve within 30 minutes of administration of nebulized epinephrine but may recur as the effects of epinephrine wear off (usually by two hours) [17,18]. Children who have recurrence or worsening of moderate to severe symptoms during the observation period should receive additional racemic epinephrine and should be admitted to the hospital. (See 'Indications for hospital admission' below.)

After three to four hours of observation, children who remain comfortable may be discharged home if they meet the following criteria [13-16]:

●No stridor at rest

●Normal pulse oximetry

●Good air exchange

●Normal color

●Normal level of consciousness

●Demonstrated ability to tolerate fluids by mouth

●Caregivers understand the indications for return to care and would be able to return if necessary

Before discharge, follow-up with the primary care provider should be arranged within the next 24 hours. Instructions regarding home treatment should be provided. (See 'Home treatment' above.)

Approximately 5 percent of children well enough for discharge from the ED after receiving corticosteroids and nebulized epinephrine treatments are expected to return for care [19,20]. Relapse within 24 hours is unlikely in those who have minimal symptoms at the time of discharge. (See 'Recurrent symptoms' below.)

Indications for hospital admission — Patients with ongoing severe symptoms after initial treatment should receive additional nebulized epinephrine and should be admitted to the hospital. Nebulized epinephrine can be repeated every 15 to 20 minutes. The administration of three or more doses within a two- to three-hour time period should prompt initiation of close cardiac monitoring if this is not already underway. (See 'Monitoring' below.)

Children with persistent moderate symptoms can be observed for at least four hours before deciding whether they require hospital admission as the effect of dexamethasone may not be apparent for several hours [3].

Indications for inpatient admission include [3,21]:

●Severe croup with poor air entry, altered consciousness, or impending respiratory failure

●Moderate/severe croup with persistent or deteriorating respiratory distress after treatment with nebulized epinephrine and corticosteroids

●"Toxic" appearance or clinical picture suggesting serious secondary bacterial infection

●Need for supplemental oxygen

●Severe dehydration

Additional factors that influence the decision regarding admission include [3,21]:

●Young age, particularly younger than six months

●Recurrent visits to the ED within 24 hours

●Ability of the family to comprehend the instructions regarding recognition of features that indicate the need to return for care

●Ability of the family to return for care (eg, distance from home to care site, weather/travel conditions)

Admission to the pediatric intensive care unit (PICU) is warranted if any of the following are present:

●Respiratory failure requiring endotracheal intubation

●Persistent severe symptoms requiring frequent nebulized epinephrine dosing

●Underlying conditions placing the child at high risk for progressive respiratory failure (eg, neuromuscular disease or bronchopulmonary dysplasia)

Approximately 5 to 10 percent of children with croup presenting to the ED require hospitalization; only 1 percent require admission to the PICU [19,20,22-24]. Children who are admitted typically have a brief inpatient stay, and most do not require further nebulized epinephrine treatments or airway interventions [22,24,25].

Inpatient management — Children admitted to the hospital for management of croup should receive close respiratory monitoring and supportive care.

Supportive care — Supportive care for children hospitalized with moderate to severe croup includes:

●Fluids – Administration of IV fluids may be necessary in some children. Fever and tachypnea may increase fluid requirements, and respiratory difficulty may prevent the child from achieving adequate oral intake. (See "Maintenance intravenous fluid therapy in children".)

●Fever control – High fever can contribute to tachypnea and respiratory distress in children with croup, and treatment with antipyretics can improve work of breathing and insensible fluid losses.

●Comfort – Care must be taken to avoid provoking agitation or anxiety in children with moderate to severe croup as this can worsen the degree of respiratory distress and airway obstruction. Children with severe croup should be approached cautiously, and unnecessary invasive interventions should be avoided. The parent or caregiver should be instructed to hold and comfort the child and to assist in care. The use of sedatives or anxiolytics to reduce agitation is discouraged as this may cause respiratory depression.

Respiratory care — Respiratory support for children hospitalized with croup may include the following:

●Nebulized epinephrine – Repeated doses of nebulized epinephrine may be warranted for children with moderate to severe distress; however, many children admitted for management of croup will not require subsequent epinephrine treatments [24,26-28]. One study of 628 hospitalizations for croup found that only approximately 20 percent required additional nebulized epinephrine during the inpatient stay [24]. Nebulized epinephrine can be repeated every 15 to 20 minutes. However, children who require frequent doses of epinephrine (eg, more frequently than every one to two hours) should be admitted/transferred to an ICU for close cardiopulmonary monitoring. (See 'Monitoring' below and 'Nebulized epinephrine' below.)

●Supplemental oxygen – Oxygen should be administered to children who are hypoxemic (oxygen saturation of <92 percent in room air). Supplemental oxygen should be humidified to decrease drying effects on the airways since drying may impede the physiologic removal of airway secretions via mucociliary and cough mechanisms. (See "Continuous oxygen delivery systems for the acute care of infants, children, and adults".)

●Mist – Humidified air is frequently used in the treatment of croup, although studies evaluating its efficacy have found only marginal improvement in croup scores [29]. Mist therapy may provide a sense of comfort and reassurance to both the child and family; however, if the child is instead agitated by the mist, it should be discontinued. (See 'Mist therapy' below.)

●Heliox – Heliox is a mixture of helium (70 to 80 percent) and oxygen (20 to 30 percent). Heliox may decrease the work of breathing in children with severe croup by reducing turbulent airflow [30]. While heliox is not a routine intervention for children with croup, it is a reasonable intervention for children with severe respiratory distress. In this setting, it can be used as a temporizing measure to prevent the need for intubation while waiting for glucocorticoids to decrease airway edema. An important limitation of heliox use is the low fractional concentration of inspired oxygen (FiO₂) in the gas mixture, which may not be adequate for children with hypoxia. (See 'Heliox' below.)

●Intubation – The need for intubation should be anticipated in children with progressive respiratory failure so that the procedure can be performed in a controlled setting, if possible. Intubation can be challenging due to the narrowed subglottic airway and should be performed with the assistance of a skilled provider (ie, an anesthesiologist or otolaryngologist). Neuromuscular blocking agents should be avoided unless the ability to provide bag-mask ventilation has been demonstrated. An endotracheal tube that is 0.5 to 1 mm smaller than would typically be used should be placed. (See 'Croup severity score' above and "Emergency endotracheal intubation in children", section on 'Endotracheal tube'.)

Endotracheal intubation is rarely required for management of croup (<3 percent of hospitalized patients in two large retrospective studies) [22,23]. In a retrospective series of 77 children with severe croup requiring intubation, the median duration of mechanical ventilation was 60 hours and 6.5 percent of patients required reintubation after the first attempt at extubation [31]. Of note, the endotracheal cuff leak (which is commonly used to assess risk of postextubation stridor) poorly predicted extubation failure in this study. One-half of the patients in this series were diagnosed with bacterial coinfection or superinfection. (See "Extubation management in the adult intensive care unit", section on 'Cuff leak'.)

Repeated corticosteroid dosing — Repeat doses of corticosteroids are not routinely necessary but may be reasonable for the occasional child who has persistent symptoms. The risk of adverse effects from corticosteroids increases with repeat dosing. (See 'Glucocorticoids' below.)

Moderate to severe symptoms that persist for more than a few days should prompt investigation for other causes of airway obstruction. (See 'Atypical course' below and "Croup: Clinical features, evaluation, and diagnosis", section on 'Differential diagnosis'.)

Monitoring — Monitoring should include close observation of mental status and respiratory status, including monitoring for stridor, hypoxia, retractions, and adequacy of air entry. Pulse oximetry monitoring is useful to detect hypoxia; however, it is not a sensitive tool for assessing the severity of croup [21]. Children who require ongoing epinephrine treatments more frequently than every one to two hours should have continuous cardiac monitoring, though adverse cardiac effects are rare.

Infection control — Children who are admitted to the hospital with croup should be managed with contact precautions (ie, gown and gloves for contact), particularly if parainfluenza or respiratory syncytial virus is the suspected etiology. If influenza is suspected, droplet isolation measures (ie, respiratory mask within three feet) also should be followed. (See "Infection prevention: Precautions for preventing transmission of infection".)

Discharge criteria — Children who require hospital admission may be discharged when they meet the following criteria:

●No stridor at rest

●Normal pulse oximetry in room air

●Good air exchange

●Normal color

●Normal level of consciousness

●Demonstrated ability to tolerate fluids by mouth

Rebound symptoms are fairly common, particularly in children with severe croup. Thus, patients should be monitored for several hours to ensure they consistently meet these criteria. In one study of 275 children with croup admitted to the PICU, 37 percent developed rebound symptoms after initially meeting hospital discharge criteria [32]. The median time to occurrence of rebound symptoms was 13 hours. In another study of >6000 patients hospitalized for croup, 3 percent were readmitted for croup within 30 days after discharge [22]. (See 'Recurrent symptoms' below.)

Atypical course — Children admitted for croup typically remain in the hospital for <36 hours [22,26]. The child who does not show improvement as expected (over the course of one to two days) may have an underlying airway abnormality or may be developing a complication of croup. Further evaluation with radiographs of the soft tissues of the neck or consultation with otolaryngology may be warranted. A biphasic illness with poor response to nebulized epinephrine in conjunction with high fever and toxic appearance should prompt consideration of bacterial tracheitis (picture 1) [3]. (See "Croup: Clinical features, evaluation, and diagnosis", section on 'Differential diagnosis' and "Bacterial tracheitis in children: Clinical features and diagnosis".)

SPECIFIC THERAPIES FOR CROUP

Glucocorticoids — Glucocorticoids have been shown to improve croup scores, reduce the need for epinephrine, decrease length of stay in the emergency department (ED) or hospital, and reduce unscheduled medical visits [10,33-35]. Among the available agents, we suggest dexamethasone for most children because it is the agent most extensively studied and is inexpensive, is easy to administer, and has a longer duration of action compared with other agents. Oral prednisolone is a reasonable alternative for children with mild croup. Nebulized budesonide is an alternative option for children who are vomiting and who lack intravenous (IV) access.

The anti-inflammatory actions of glucocorticoids are thought to decrease edema in the laryngeal mucosa of children with croup. Improvement is usually evident within six hours of administration but seldom is dramatic [10,36].

Efficacy — Glucocorticoids have been shown to be effective in croup of all levels of severity [10,34]. Dexamethasone (oral or intramuscular [IM]), prednisolone, and budesonide (inhaled) are the agents used in the majority of studies. In a meta-analysis of 10 trials (1679 children), glucocorticoids reduced the rate of return visits and hospital admission or readmission compared with placebo (risk ratio 0.52, 95% CI 0.36-0.75) [10]. Glucocorticoids also reduced croup symptom scores at 2, 6, 12, and 24 hours and reduced hospital length of stay by approximately 15 hours (95% CI 6-24 hours). There was no apparent difference in need for intubation between the glucocorticoid group and placebo group; however, there were very few events in either group.

The efficacy of glucocorticoids may differ depending on the specific agent and dose used, as discussed below. (See 'Agents' below.)

Adverse effects — Side effects associated with short-term glucocorticoid therapy may include hyperglycemia and behavioral changes; severe adverse effects are uncommon [10,37-40]. In clinical trials evaluating a single dose of glucocorticoids in croup, few serious adverse effects were reported; however, most of these studies were too small to sufficiently evaluate rare (<1 percent) adverse effects [10,37,38,41,42].

The primary concern is potential risk of progressive viral infection or secondary bacterial infection, which have been reported in patients who received glucocorticoid treatment over several days [41], or received nebulized dexamethasone and had neutropenia [43]. These complications have not been described in children who have received single doses of oral, IM, or IV glucocorticoids for croup. In placebo-controlled clinical trials, rates of secondary bacterial infection were low and similar in patients treated with steroids compared with placebo [10].

Administration of glucocorticoids may mask the presentation of steroid-responsive upper airway lesions, such as hemangiomas, which also can present with stridor, particularly during a viral upper respiratory tract infection [44]. (See "Infantile hemangiomas: Epidemiology, pathogenesis, clinical features, and complications".)

Agents — Glucocorticoid agents that have been used for croup include:

●Dexamethasone – Dexamethasone is our preferred glucocorticoid agent for most children with croup. It is the agent most extensively studied in this setting [10].

•Route – Dexamethasone can be given IM, IV, or orally and should generally be administered via the least invasive route possible (orally if oral intake is tolerated, IV if IV access has been established, or IM if oral intake is not tolerated and IV access has not been established). The oral liquid preparation of dexamethasone (1 mg per mL) has a foul taste. The IV preparation is more concentrated (4 mg per mL) and can be given orally mixed with syrup [3,11].

Based on the available evidence, there do not appear to be clinically significant differences in croup outcomes between IM and orally administered dexamethasone [10]. Nebulized dexamethasone appears to be less effective than oral dexamethasone in reducing the need for additional treatments and preventing return visits [45].

•Dose – The optimal dose of dexamethasone in children with croup is uncertain. In clinical trials, doses ranging from 0.15 to 0.6 mg/kg have been shown to be effective [10]. The maximum dose of dexamethasone used in these trials ranged from 10 mg to 20 mg, with most using 16 mg. For children with moderate to severe croup (ie, Westley croup score of ≥3 (table 1)), we suggest a single dose of 0.6 mg/kg (maximum 16 mg) [46]. Dexamethasone at this dose has proven efficacy in croup, as demonstrated in numerous clinical trials, including several high-quality placebo-controlled trials [10,12,35,45]. Based on these data, we also suggest a dose of 0.6 mg/kg (maximum 16 mg) for children with mild croup (ie, Westley croup score of ≤2 (table 1)); however, limited data suggest that lower doses (0.15 mg/kg to 0.4 mg/kg) may be equally effective in patients with mild croup [10,47-50]. Nonpharmacologic management is another reasonable alternative for patients with mild croup. (See 'Mild croup' above.)

•Comparison with other agents – Dexamethasone has comparable or superior efficacy for treatment of croup compared with other glucocorticoids that have been evaluated [10,51]. In a meta-analysis of four trials (374 children) directly comparing dexamethasone with inhaled budesonide, dexamethasone achieved greater improvement in croup scores at 6 and 12 hours; however, rates of return visits or hospital admission or readmission were not appreciably different [10]. Studies comparing dexamethasone and prednisolone are discussed in the following section. Data comparing dexamethasone with other agents (eg, beclomethasone, betamethasone, fluticasone) are limited to single small clinical trials, and thus it is difficult to draw firm conclusions [10].

●Prednisolone – For children with mild croup who are managed as outpatients, oral prednisolone (single dose of 1 mg/kg) is an alternative to oral dexamethasone [52]. The advantage of prednisolone is that it is more palatable than the oral liquid preparation of dexamethasone and may be easier for young children to take. In addition, prednisolone is widely available in most outpatient settings, whereas dexamethasone may not be as available.

Based on the available data, prednisolone appears to be effective in improving croup symptoms in mildly affected patients; however, there may be an increased risk of symptom recurrence with prednisolone compared with dexamethasone [10,51].

In a randomized trial involving >1200 children with predominantly mild croup (Westley croup scores were ≤3 in 93 percent of patients) managed in the outpatient or ED setting, similar improvements in croup scores were seen in patients treated with a single dose of oral prednisolone (1 mg/kg) compared with dexamethasone (at either standard-dose [0.6 mg/kg] or low-dose [0.15 mg/kg]) [51]. The proportion of children who recovered within two hours of treatment was similar in all three groups (68 versus 70 and 74 percent, respectively). Fewer children in the standard-dose dexamethasone group had return visits for recurrent symptoms compared with prednisolone (18 versus 22 percent); however, this finding was not statistically significant. In a meta-analysis of three earlier and smaller trials, the rate of return visits for recurrent symptoms was significantly lower with dexamethasone compared with prednisolone (8 versus 20 percent; risk ratio 0.39, 95% CI 0.19-0.79) [10].

●Budesonide – Nebulized budesonide is not routinely used in croup because it is more expensive and more difficult to administer than IM or oral dexamethasone; however, it may provide an alternative to IM or IV dexamethasone for children with vomiting or severe respiratory distress in whom IV access cannot be readily obtained [46]. In children with severe respiratory distress, a single dose of budesonide may be mixed with epinephrine and administered simultaneously. In clinical trials, nebulized budesonide appears to have similar efficacy compared with IM or oral dexamethasone [10,11,53-55].

●Beclomethasone – Inhaled beclomethasone has been evaluated in a single small randomized trial in 39 children with croup [56]. Improvements in croup scores and the rate of return visits was similar to that of children treated with IM dexamethasone. However, the small study size (39 patients) makes it difficult to draw firm conclusions.

●Betamethasone – A pilot study compared the effectiveness of a single oral dose of betamethasone (0.4 mg/kg) with a single dose of IM dexamethasone (0.6 mg/kg) in 52 children with mild to moderate croup who were treated in the ED [57]. Despite randomization, mean baseline croup scores were higher in the dexamethasone group (3.6 versus 2). Croup scores declined significantly in both groups, and there were no differences between groups in mean croup scores four hours after treatment, rate of hospitalization, time to resolution of symptoms, need for additional treatment, or number of return visits to the ED.

●Fluticasone – In a small trial in 17 children hospitalized for croup, inhaled fluticasone did not improve croup scores or reduce length of hospital stay compared with placebo [58].

●Prednisone – The use of prednisone in the management of croup has not been evaluated in clinical trials. However, it has equivalent potency to prednisolone and, in theory, should have similar effects.

Nebulized epinephrine — Nebulized epinephrine is effective for reducing stridor and work of breathing in children with croup [1,59,60]. It is used for acute symptom relief in patients with moderate to severe croup. Epinephrine has rapid onset and works by decreasing airway edema, which helps relieve airway obstruction [61]. Even a small relief in airway swelling can result in considerable short-term clinical improvement. However, epinephrine does not alter the natural history of croup.

●Racemic versus L-epinephrine – Racemic epinephrine (which is a 1:1 mixture of the D- and L-isomers) and L-epinephrine appear to have similar efficacy and a similar side effect profile [17]. Thus, either form of epinephrine is acceptable to use for treatment of croup. Racemic epinephrine is not available in some areas outside of the United States.

●Dose – Doing and administration of nebulized epinephrine are as follows:

•Racemic epinephrine is administered as 0.05 mL/kg per dose (maximum of 0.5 mL) of a 2.25% solution diluted to 3 mL total volume with normal saline. It is given via nebulizer over 15 minutes.

•L-epinephrine is administered as 0.5 mL/kg per dose (maximum of 5 mL) of a 1:1000 dilution [17]. It is given via nebulizer over 15 minutes.

Nebulized epinephrine treatments may be repeated every 15 to 20 minutes if warranted by the degree of symptoms. However, children who require frequent doses of epinephrine (eg, more frequently than every one to two hours) should be admitted/transferred to an intensive care unit (ICU) for close cardiopulmonary monitoring. (See 'Monitoring' above.)

●Efficacy – In a meta-analysis of eight placebo-controlled trials (225 patients), nebulized epinephrine improved 30-minute posttreatment croup scores in children with moderate to severe croup [59]. The mean reduction in croup score from baseline in the individual trials ranged from 2.2 to 3.6 (compared with approximately 1 in the placebo group). However, the benefit dissipated by two hours post-treatment [1,62].

The method of administration varied in the trials, with some using simple nebulization and others using intermittent positive pressure breaths [1,59,62,63]. A study comparing these two methods found them to be similarly effective [64]. Thus, simple nebulization is the method used most commonly in clinical practice.

●Side effects and cautions – Serious adverse effects from nebulized epinephrine are rare. Children who require ongoing epinephrine treatments more frequently than every one to two hours should be admitted/transferred to an ICU for close cardiopulmonary monitoring. Adverse cardiac effects (eg, arrhythmia, myocardial ischemia) from nebulized epinephrine have rarely been reported [65]. (See 'Monitoring' above.)

In addition to the potential for adverse cardiac effects, it is important for clinicians to be aware that since the clinical effects are short-lived (typically lasting for no more than two hours), some children may experience a "rebound phenomenon," wherein croup symptoms worsen or recur as the effects of epinephrine wear off. Thus, children who receive even a single dose of nebulized epinephrine should be observed in the ED or hospital setting for at least three to four hours after administration to ensure that symptoms do not recur. (See 'Discharge to home' above.)

Heliox — Helium is an inert, nontoxic, low-density gas. Heliox is a mixture of helium (70 to 80 percent) and oxygen (20 to 30 percent). Because of its lower density, heliox flows through narrow airways with less turbulence and resistance than oxygen-nitrogen mixtures. (See "Physiology and clinical use of heliox".)

Heliox is not a routine intervention for children with croup, but it may decrease the work of breathing in children with severe respiratory distress and can be used as a temporizing measure to prevent the need for intubation while waiting for glucocorticoids to decrease airway edema [66].

In clinical trials involving children with mild to moderate croup, heliox has not definitively been shown to be more effective than humidified oxygen for reducing croup symptoms [30,67-69]. A 2018 systematic review identified only three methodologically limited clinical trials (91 patients) evaluating heliox in children with croup [30]. In the largest trial (n = 47), heliox modestly improved croup scores at one hour after initiating treatment (mean difference -1.1, 95% CI -1.96 to -0.24), but the difference at two hours was no longer statistically significant (mean difference -0.7, 95% CI -1.56 to 0.16) [69]. No conclusion could be reached as to whether heliox reduced the need for hospitalization since few patients in either treatment group required hospitalization (one in the heliox group, two in the control group).

Mist therapy — Humidified air is frequently used in the treatment of croup, although studies supporting its efficacy in reducing symptoms are limited. Two randomized trials (one comparing mist versus no mist and the other comparing no mist, low humidity, and 100 percent humidity) among children brought to an ED for croup found that the changes in croup scores from baseline were similar in children treated with and without mist [70,71].

Although humidified air does not reduce subglottic edema, it may provide other benefits. Inhalation of moist air, relative to dry air, may decrease drying of inflamed mucosal surfaces and reduce inspissation of secretions [72]. In addition, a mist source may provide a sense of comfort and reassurance to both the child and family [73-75]. In medical settings, mist therapy may be provided by blow-by or saline nebulization treatments. Croup tents should be avoided since they can aggravate a child's anxiety and make vital signs and other visual assessments of the child more difficult. Some guidelines recommend against the use of mist therapy for children who are hospitalized with croup [46]. Certainly, if the child is agitated by the provision of mist, mist therapy should be discontinued.

Therapies not routinely recommended — Antibiotics, antitussives, decongestants, and sedatives generally do not play a role in management of croup.

●Antibiotics – Antibiotics have no role in the routine management of uncomplicated croup, since most cases are caused by viruses [37]. Antibiotics should be used only to treat specific bacterial complications, such as tracheitis. (See "Bacterial tracheitis in children: Treatment and prevention", section on 'Antibiotic therapy'.)

●Antitussives and decongestants – Over-the-counter antitussive and decongestant medications are of unproven benefit for croup and should generally be avoided in children <2 years due to risk of adverse effects [46,76]. Opioid-containing cough and cold medicines (eg, codeine) should be avoided in all children [77].

●Sedatives – The use of sedative agents in effort to improve airway obstruction by relieving anxiety and apprehension is not recommended. Sedatives may treat the symptom of agitation while masking the underlying causes of air hunger and hypoxia. They also may decrease respiratory effort (and therefore croup scores), without improving ventilation [37,78].

FOLLOW-UP — Any patient who was admitted to the hospital, received nebulized epinephrine, or had a prolonged outpatient visit should have follow-up scheduled with the primary care provider within 24 hours or as soon as can be arranged. Although some children may continue to have mild to moderate symptoms at the time of follow-up, the available evidence does not support routine use of corticosteroid therapy beyond 24 hours.

Follow-up should continue until the child's symptoms have begun to resolve. The child whose symptoms do not resolve over the course of approximately seven days may have an underlying airway abnormality or may be developing a complication of croup. (See 'Atypical course' above.)

OUTCOME — Symptoms of croup resolve in most children within three days but may persist for up to one week [22,41,79]. Approximately 8 to 15 percent of children with croup require hospital admission [19,37], and, among those, <3 percent require intubation [22,23]. Mortality is rare, occurring in <1 percent of intubated children [22,80].

Complications — Complications of croup are uncommon. Children with moderate to severe croup are at risk for respiratory failure. Other complications include postobstructive pulmonary edema, pneumothorax, and pneumomediastinum [81,82]. These complications can be anticipated and managed by intensive monitoring and intervention in the medical setting. Out-of-hospital cardiac arrest and death also have been reported [83].

Secondary bacterial infections may arise from croup. Bacterial tracheitis, bronchopneumonia, and pneumonia occur in a small number of patients [41,84]. In most instances, the child has been relatively stable or beginning to improve after several days of illness, but then suddenly worsens, with higher or recurrent fever, increased (and potentially productive) cough, and/or respiratory distress. (See "Bacterial tracheitis in children: Clinical features and diagnosis", section on 'Clinical features' and "Community-acquired pneumonia in children: Clinical features and diagnosis", section on 'Clinical presentation'.)

Recurrent symptoms — Approximately 5 percent of children treated for croup in the outpatient setting have repeat visits for recurrent symptoms within seven days following discharge [19,22].

Children who have recurrent episodes of croup should be referred to an otolaryngologist to evaluate for underlying airway abnormalities (eg, laryngomalacia, subglottic stenosis, reflux changes, hemangioma). In the available cases series, clinically significant airway abnormalities were reported in approximately 10 percent of children referred to otolaryngologists for recurrent croup [85-91]. (See "Croup: Clinical features, evaluation, and diagnosis", section on 'Recurrent croup' and "Assessment of stridor in children".)

Although an association between recurrent croup and gastroesophageal reflux has been reported, it is unclear if there is a causal relationship [92]. (See "Clinical manifestations and diagnosis of gastroesophageal reflux disease in children and adolescents", section on 'Other conditions'.)

Some children with recurrent croup follow a fairly typical pattern referred to as "spasmodic croup," which is characterized by intermittent episodes of exclusively nighttime symptoms with abrupt onset and cessation and relative wellness between episodes. This occurs most commonly in children with allergic conditions or family history of allergies. Spasmodic croup usually has a benign course and most children outgrow it by school age. (See "Croup: Clinical features, evaluation, and diagnosis", section on 'Spasmodic croup'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Croup".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient education" and the keyword[s] of interest.)

●Basics topic (see "Patient education: Croup (The Basics)")

●Beyond the Basics topic (see "Patient education: Croup in infants and children (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Severity assessment – Management of children with croup begins with an assessment of severity (table 1) (calculator 1). This can be accomplished via telephone triage or by examining the child in the office or emergency department (ED) setting. If concerns arise on telephone triage (eg, stridor at rest, underlying airway abnormality, previous episodes of moderate to severe croup, underlying conditions that may predispose to respiratory failure, rapid progression of symptoms, inability to tolerate fluids, prolonged symptoms, or atypical course), the child should be seen in the office or ED. (See 'Severity assessment' above and 'Telephone triage' above.)

●Initial management – Management of croup is based on the severity of symptoms (algorithm 1 and table 1) (calculator 1):

•Mild croup – Children with mild symptoms (ie, no stridor at rest and no respiratory distress) can be managed at home. Families should be instructed in provision of supportive care and indications to seek medical attention. For children with mild croup who are seen in the office or ED setting, we suggest a single dose of dexamethasone or prednisolone rather than supportive care alone (algorithm 1) (Grade 2B). In this setting, the appropriate dose of dexamethasone is 0.15 to 0.6 mg/kg (maximum 16 mg) given orally. Prednisolone is given orally at a dose of 1 mg/kg. Nonpharmacologic management is a reasonable alternative, particularly if the family has concerns about side effects from glucocorticoids. (See 'Mild croup' above and 'Glucocorticoids' above.)

•Moderate to severe croup – Children with moderate croup (ie, stridor at rest with mild to moderate retractions) should be evaluated in the office or ED, and those with severe croup (stridor at rest with marked retractions and significant distress or agitation) should be evaluated in the ED. Children with severe croup must be approached cautiously as any increase in anxiety may worsen airway obstruction. Initial management includes the following (see 'Moderate to severe croup' above):

-For children with moderate to severe croup, we recommend initial treatment with nebulized epinephrine and a single dose of glucocorticoid (dexamethasone) rather than either drug alone or nonpharmacologic management (Grade 1B). (See 'Initial treatment' above and 'Glucocorticoids' above and 'Nebulized epinephrine' above.)

-Dexamethasone – We suggest dexamethasone rather than other glucocorticoids for treatment of moderate to severe croup (Grade 2C). We prefer dexamethasone because it is the agent most extensively studied and is inexpensive, is easy to administer, and has a longer duration of action compared with other agents. Dexamethasone is given at a dose of 0.6 mg/kg (maximum of 16 mg) by the least invasive route (algorithm 1). (See 'Agents' above.)

-Nebulized epinephrine – Dosing of nebulized epinephrine depends on the product used. Racemic epinephrine is administered as 0.05 mL/kg per dose (maximum of 0.5 mL) of a 2.25% solution diluted to 3 mL total volume with normal saline. L-epinephrine is administered as 0.5 mL/kg per dose (maximum of 5 mL) of a 1:1000 dilution. In both cases, it is given via nebulizer over 15 minutes. Nebulized epinephrine can be repeated every 15 to 20 minutes. The administration of three or more doses within a two- to three-hour time period should prompt initiation of close cardiac monitoring if this is not already underway. (See 'Nebulized epinephrine' above.)

-Supportive care – Supportive care includes humidified air or oxygen, antipyretics, and encouragement of fluid intake. (See 'Supportive care' above.)

-Observation and disposition – Children with moderate to severe croup should be observed for three to four hours after intervention. Those who improve may be discharged home. Children with persistent or worsening symptoms during the observation period should be admitted to the hospital. (See 'Discharge to home' above and 'Indications for hospital admission' above.)

•Hospital management – Management of children hospitalized for croup includes (see 'Inpatient management' above):

-Ongoing supportive care with provision of intravenous (IV) fluids and fever reduction. (See 'Supportive care' above.)

-Respiratory care with repeated doses of nebulized epinephrine, as indicated by respiratory distress, and administration of humidified air or oxygen, as indicated by hypoxemia. (See 'Respiratory care' above.)

-For most patients, we suggest not routinely using repeated doses of glucocorticoids (Grade 2C). However, repeat dosing may be reasonable for the occasional child who has persistent symptoms. (See 'Repeated corticosteroid dosing' above.)

-Monitoring for worsening respiratory distress. (See 'Monitoring' above.)

●Persistent or recurrent symptoms – Children who have moderate to severe symptoms that persist for more than a few days or recurring episodes of croup not associated with other manifestations of a viral illness (no fever and/or rhinorrhea) should undergo investigation for other causes of upper airway obstruction. (See 'Atypical course' above and 'Recurrent symptoms' above and "Croup: Clinical features, evaluation, and diagnosis", section on 'Differential diagnosis'.)

●Follow-up – Most children with croup recover uneventfully. Children who received nebulized epinephrine, had a prolonged outpatient visit, or were admitted to the hospital should have follow-up scheduled with the primary care provider within 24 hours of discharge or as soon as follow-up can be arranged. (See 'Follow-up' above and 'Outcome' above.)