INTRODUCTION — Otitis media with effusion (OME), also called serous otitis media or "glue ear" (picture 1), is defined as middle ear effusion without signs of acute infection [1]. OME often occurs after acute otitis media (AOM), but it also may occur with Eustachian tube dysfunction in young children, in the absence of a preceding AOM.
The clinical features and diagnosis of OME will be reviewed here. The management of OME and the clinical features, diagnosis, treatment, and prevention of AOM are discussed separately:
●(See "Otitis media with effusion (serous otitis media) in children: Management".)
●(See "Acute otitis media in children: Epidemiology, microbiology, and complications".)
●(See "Acute otitis media in children: Clinical manifestations and diagnosis".)
●(See "Acute otitis media in children: Treatment".)
●(See "Acute otitis media in children: Prevention of recurrence".)
TERMINOLOGY
●Otitis media with effusion (OME)/serous otitis media – Middle ear effusion without signs of acute infection (picture 1) [1].
●"Glue ear" – A term sometimes used as a synonym for OME but that should be reserved for cases in which the effusion is long standing and the fluid in the middle ear has become thick and glue-like, as observed during myringotomy before tympanostomy tube insertion [2].
EPIDEMIOLOGY — OME frequently occurs after an episode of acute otitis media (AOM). In such cases, the middle ear effusion may persist for a few weeks after the acute symptoms have resolved (figure 1) [3-5]. Some children develop chronic OME, defined as OME that persists for three months or longer, without any signs of acute inflammation. The epidemiology of AOM is discussed separately. (See "Acute otitis media in children: Epidemiology, microbiology, and complications", section on 'Epidemiology'.)
OME is common among apparently asymptomatic young children [6,7]. In three birth cohorts of children who were serially examined with tympanometry and/or otoscopy, 90 percent of children (80 percent of ears) had at least one episode of OME by four years of age [6]. The prevalence ranged from 10 to 17 percent among children two through four years of age, and then decreased to 3 to 4 percent between six and eight years. Similar rates have been noted in other cohorts [7,8]. The Danish longitudinal birth cohort reported a cumulative "otitis media" incidence of 61 percent at seven years [9]. However, the questionnaire did not distinguish between AOM, OME, and chronic suppurative otitis media. The OME burden was 26 percent, as represented by the proportion of children younger than seven years who received at least one tympanostomy tube between 1996 and 2003. OME is more common in the winter than in the summer [6].
Dramatic declines in the burden of OME were observed during the first months of the coronavirus disease 2019 (COVID-19) pandemic [10-12]. This likely resulted from a combination of mitigation measures (eg, school closures, physical distancing, face masks, travel restrictions), as well as viral interference with virtual absence of seasonal respiratory viruses from the community. Later in the pandemic, with the relaxation of mitigation measures, introduction of COVID-19 vaccines for adults and children, replacement of the alpha variant by other variants, and the return of seasonal respiratory viruses, OME prevalence has once again increased as a "rebound" effect [13].
Indigenous children from Pacific Island/Māori, Aboriginal Australian, Inuit, and Native American populations are at increased risk for the development of OME and recurrent AOM [14-16]. Both of these middle ear conditions are risk factors for chronic suppurative otitis media, which affects >25 percent of children in some of these populations. (See "Chronic suppurative otitis media (CSOM): Clinical features and diagnosis", section on 'Epidemiology'.)
PREDISPOSING FACTORS — Family history of otitis media (otitis-prone parents), bottle feeding (as opposed to breastfeeding), male sex, daycare center or in-person school attendance, adenoidal hypertrophy, exposure to tobacco smoke, and low socioeconomic status are important risk factors for development of OME and acute otitis media [7,10,17-20]. Children with a cleft palate and other midface facial anomalies, such as Down syndrome, are particularly prone to chronic OME. Children with obesity or who are overweight also appear to be at increased risk for OME and recurrent OME [21,22]. (See "Acute otitis media in children: Epidemiology, microbiology, and complications", section on 'Risk and protective factors'.)
PATHOGENESIS — The pathogenesis of OME is incompletely understood. OME appears to be a multifactorial condition that can result from a variety of inciting events that converge on a common pathway of inflammation, infection, effusion, and tissue hyperplasia. The interplay of inflammation, innate immunity, mucus overproduction, presence of viruses and bacteria, proliferation of mucus-secreting goblet cells in the epithelial lining of the anteroinferior middle ear cleft and eustachian tube immaturity and its rather horizontal position in children all contribute to the development and persistence of middle ear effusion.
The classic model has been that OME results from chronic inflammation in response to persistent bacterial components following acute otitis media (AOM). However, the pathogenesis appears to be more complicated [23]. Eustachian tube dysfunction is a major factor contributing to the persistence of effusion in the middle ear cavity [24]. Evidence suggests that bacterial biofilms also have a major role in the pathogenesis [25-27], and despite usually being culture-negative at myringotomy before tympanostomy tube insertion, immunofluorescence studies and sensitive polymerase chain reaction assays demonstrate bacterial deoxyribonucleic acid (DNA; most commonly from nontypeable Haemophilus influenzae) present in the middle ear. Poor clearance of middle ear biofilms [28,29], genetic predisposition [30,31], allergies [32-39], ciliary dyskinesia [40], gastroesophageal reflux [41], and obesity [42] also may contribute.
A bacterial pathogen is identified in approximately one out of three middle ear effusions of children with OME who undergo myringotomy and insertion of tympanostomy tubes, often without evidence of inflammation and primarily in children younger than two years [43-48]. The pathogens most commonly recovered include those that typically cause AOM (Streptococcus pneumoniae, nontypeable H. influenzae, and Moraxella catarrhalis). Microbiome studies revealed that H. influenzae is the predominant taxa in the nasopharynx and middle ear fluid in children with OME, but a multitude of other bacterial species (eg, Alloiococcus spp, Staphylococcus spp, and Turicella spp) are also present within middle ear effusions and may serve as a source of potential infection [47,49-51].
Biofilms appear to play an important role in the pathogenesis of OME. Biofilm formation by bacterial otopathogens permits persistence and aggregation of bacteria on the middle ear mucosa, often in the absence of positive bacterial cultures. Biofilm-associated pathogens are unresponsive, in general, to antibiotic treatment. Support for the role of biofilms in the pathogenesis of OME is provided by observational studies demonstrating viable bacteria within a biofilm in an animal model [25]; bacterial DNA, messenger ribonucleic acid (RNA), and newly synthesized protein in the middle ear fluid of patients with OME [27]; and mucosal biofilms in biopsy specimens from the middle ears of children undergoing tympanostomy tube placement for the treatment of OME and/or recurrent AOM, but not in those of control children undergoing cochlear implantation [26,52]. Biofilms have also been described on the tympanic membrane itself in children scheduled for tympanostomy tubes and on tympanostomy tubes extracted from children [53]. In in vitro experiments, biofilms formed on tympanostomy tubes within a few days and can be associated with persistent otorrhea [54].
The contribution of allergies to the pathogenesis of OME is controversial. In observational studies, there is an association between allergic rhinitis and OME [32-37]. The effect of allergic rhinitis is age dependent, and it is more pronounced in younger patients [39]. In addition, allergic mediators (immunoglobulin E [IgE], activated mast cells, tryptase, myeloperoxidase) have been detected in the middle ears of patients with OME [33,38]. However, in an animal model, middle ear challenge with antigenic material did not produce effusion [55]. In addition, in randomized trials, intranasal glucocorticoids and antihistamine agents (which are effective in the treatment of allergic rhinitis) do not provide long-term benefit to the treatment of OME [56]. (See "Pharmacotherapy of allergic rhinitis", section on 'Efficacy and onset of action' and "Otitis media with effusion (serous otitis media) in children: Management", section on 'Intranasal glucocorticoids'.)
Gastroesophageal reflux disease (GERD) is also hypothesized to contribute to OME, but causality has not been proven and study findings are inconsistent [57-59].
CLINICAL FEATURES
Presentation — Clinical signs of acute infection are absent in patients with OME, by definition. In the majority of patients, OME is transient and does not come to medical attention.
When patients are symptomatic, the predominant symptom is hearing loss. The average loss with OME is approximately 28 decibels (dB), but it varied greatly from study to study [60]. OME is usually diagnosed in preschool children, who may complain of hearing loss or have speech and language delays. It may also be detected during newborn hearing screening, school hearing screening, or audiology screening [61]. Although the hearing loss is usually mild, some children with OME present with caregiver concerns about hearing, language development, behavior, or school performance [2,20,61].
Hearing loss
Failed newborn hearing screen — Infants who fail their newborn hearing screen may have OME. In a prospective study that included 152 infants referred for failed newborn hearing screening with auditory brainstem response, 55 percent had OME [62]. Infants who fail the newborn hearing screen and demonstrate middle ear disease before age six months usually require early tympanostomy tube insertion. Expeditious resolution of OME is necessary to detect sensorineural hearing deficits in infancy.
Conductive hearing loss — In children with OME, conductive hearing loss is typically mild to moderate and fluctuating [2]. Studies of children with OME demonstrate the median loss to be 25 dB [63], which is the equivalent of putting plugs in your ears. In a large prospective study, children younger than three years with bilateral middle ear effusion had hearing thresholds that were approximately 10 to 15 dB higher than similarly aged children without middle ear effusion [64].
Young children typically do not complain of hearing impairment. However, caregivers may note that the child frequently says "What?," asks for things to be repeated, asks for the volume to be turned up on sound-generating devices (eg, television), has difficulty hearing in noisy backgrounds, or hears things incorrectly when not looking directly at the speaker [2,61]. Older children are better able to recognize the mild, fluctuating hearing impairment.
The clinical significance of the mild and fluctuating conductive hearing loss associated with OME in otherwise healthy children is debated. Although hearing loss may adversely affect binaural processing, sound localization, and speech perception in a noisy background [63,65-68], these adverse effects do not occur if the conductive hearing loss is only mild, as it typically is when associated with OME. In a systematic review of randomized trials of tympanostomy tubes for hearing loss associated with OME in otherwise healthy children, short-term improvement in hearing loss was observed, but there were no proven benefits on language development or cognition [69]. Although small observational studies have noted that children who have prolonged middle ear effusion have lower scores on tests of speech, language, and cognitive abilities [70-72], the child's home environment appears to have a greater impact on outcomes [73]. The impact of mild conductive hearing loss associated with persistent middle ear effusion is more significant in children with an underlying sensorineural hearing loss [74]. (See "Otitis media with effusion (serous otitis media) in children: Management", section on 'Tympanostomy tubes'.)
Other symptoms — Other symptoms that may occur in children with OME include a feeling of fullness in the ear, tinnitus, or balance problems [61,75-81]. Young children with balance problems may present with disequilibrium, instability, falling, stumbling, or clumsiness [76-79].
These symptoms are nonspecific; other causes should be considered and evaluated before attributing them to OME. (See "Evaluation of earache in children" and "Assessment of sleep disorders in children" and "Etiology and diagnosis of tinnitus" and "Causes of vertigo".)
Clinical and otoscopic findings — Otoscopic findings of OME include [1,2,75,82,83]:
●Impaired mobility of the tympanic membrane when positive pressure is applied with the bulb during pneumatic otoscopy (movie 1). However, some movement may be apparent when negative pressure is applied initially to the tympanic membrane; impaired mobility does not differentiate OME from AOM.
●Type B tympanometry (flat curve) (figure 2).
●An air-fluid level, sometimes with bubbles, may be present behind an intact tympanic membrane (picture 1); in a study correlating examination findings with expert clinical diagnosis, an air-fluid level was present in 20 of 34 cases of OME (compared with 3 of 50 cases of AOM) [82].
●Amber-colored middle ear fluid is common (picture 2A), although the fluid may be colorless with a gray or translucent tympanic membrane (picture 1); erythema of the tympanic membrane is more characteristic of AOM; in the study correlating examination findings with expert clinical diagnosis, no children with OME had marked erythema of the tympanic membrane (compared with 15 of 50 children with AOM) [82].
●Tympanic membrane in a neutral or retracted position (picture 2A-B) – Unlike the bulging or fullness of the tympanic membrane (picture 3A-B) that is a feature of AOM and helps to differentiate AOM from OME.
●Opacification of the tympanic membrane (not due to scarring) may occur but does not differentiate OME from AOM; in the study correlating examination findings with expert clinical diagnosis, opacification was present in 33 of 34 cases of OME and 50 of 50 cases of AOM [82].
Noninvasive technologies that overcome some of the objective difficulties of standard otoscopy for the diagnosis of OME are under investigation [84]. These include use of artificial intelligence algorithms, optical coherence tomography, transmastoid ultrasound, and quantitative tympanometry, among others. (See 'Diagnosis' below.)
Complications and sequelae
Hearing loss — The most significant complication of OME is conductive hearing loss, which is described above. (See 'Hearing loss' above.)
Myringosclerosis — Calcification of the connective tissue of the tympanic membrane is another potential complication of frequent episodes of middle ear infection or tympanostomy tube insertion [85]. It is characterized by whitish plaques in the tympanic membrane (picture 4). In most children, the myringosclerosis is of no functional importance.
Retraction pocket — Chronic Eustachian tube dysfunction that persists over a long time (ie, years) may result in retraction pockets of the tympanic membrane due to the negative pressure within the middle ear cavity, development of cholesteatoma, and potentially ossicular erosion.
Cholesteatoma — A cholesteatoma is the abnormal accumulation of desquamating epithelium or keratin within the middle ear. In children with OME, cholesteatoma can occur within the middle ear cavity or within a retraction pocket in the tympanic membrane (with secondary extension into the middle ear (picture 5)). Secondary extension into the middle ear may also occur if there is a tympanic membrane perforation. (See "Cholesteatoma in children".)
The cholesteatoma occasionally may enlarge to envelop the ossicles, resulting in conductive hearing loss, destruction or disarticulation of the ossicular chain, and destruction of the surrounding tissues (ie, the mastoid, facial nerve, tegmen, and lateral semicircular canal). Cholesteatoma often become secondarily infected [86]. The complications of cholesteatoma are discussed in greater detail separately. (See "Cholesteatoma in children", section on 'Natural history and complications'.)
DIAGNOSIS — OME is defined as middle ear effusion without acute signs and symptoms of infection [1,23,87]. OME is usually diagnosed with standard otoscopy, which can be used to verify both the presence of middle ear effusion and the absence of signs of infection [1,2].
Pneumatic otoscopy can be of value to determine the movement of the tympanic membrane when pressure is applied. Tympanometry and acoustic reflectometry are adjunctive tests that may be used to confirm the presence of middle ear effusion, but they are not helpful in assessing signs of inflammation.
●Pneumatic otoscopy – Diagnosis of OME requires signs of middle ear effusion without acute signs or symptoms of infection. Otoscopic signs of middle ear effusion include (see 'Clinical and otoscopic findings' above) [1,2,75,82,83]:
•Impaired mobility of the tympanic membrane (movie 1)
•Bubbles or an air-fluid level may be present (picture 1)
•Opacity of the tympanic membrane (not due to scarring)
In a meta-analysis of eight studies of pneumatic otoscopy, the sensitivity and specificity of the combination of appearance, color, and mobility of the tympanic membrane in predicting OME confirmed by myringotomy were 91 (95% CI 90-93) and 77 (95% CI 74-80) percent, respectively [2]. In individual studies, sensitivity ranged from 85 to 98 percent and specificity from 71 to 81 percent.
In a meta-analysis of three studies evaluating only mobility of the tympanic membrane, the sensitivity and specificity in predicting OME confirmed by myringotomy were 95 (95% CI 93-96) and 83 (95% CI 79-86) percent, respectively [2]. In individual studies, sensitivity ranged from 87 to 99 percent and specificity from 69 to 90 percent.
In a systematic review, compared with other diagnostic methods (eg, nonpneumatic otoscopy, tympanometry, acoustic reflectometry), pneumatic otoscopy had the best balance of sensitivity and specificity for validated observers in predicting myringotomy-confirmed OME (pooled sensitivity of 94 percent, 95% CI 91-96 percent; pooled specificity of 80 percent, 95% CI 75-86 percent) [87].
The accuracy of pneumatic otoscopy performed by less-experienced otoscopists may be less than that in published reports [88-90].
●Audiology – Audiology evaluation can facilitate the diagnosis of OME if the middle ear fluid is difficult to see (eg, clear and colorless) or the child does not tolerate pneumatic otoscopy or tympanometry. It is mandatory before tympanostomy tube surgery. Conductive hearing loss in conjunction with a flat tympanogram (figure 2) is suggestive of OME. (See "Hearing loss in children: Screening and evaluation", section on 'Formal audiology'.)
In addition, audiology is recommended at the time of diagnosis of OME for children who have, or are at risk for, speech, language, or learning disorders. For children with OME who are not at risk for speech, language, or learning problems, audiology typically is obtained if OME has persisted for ≥3 months (ie, chronic OME). (See "Otitis media with effusion (serous otitis media) in children: Management", section on 'Children at risk for speech, language, or learning issues'.)
●Tympanometry and acoustic reflectometry – Tympanometry and acoustic reflectometry may be used to confirm the presence of middle ear fluid but are not helpful in differentiating OME from acute otitis media (AOM) because they do not assess acute signs of infection. Observational studies suggest that they can be reliably performed by caregivers [91,92].
Tympanometry measures the compliance of the tympanic membrane, Eustachian tube function, and middle ear function [1]. When fluid is present in the middle ear, the tympanogram is characterized by reduced height of the curve (ie, the middle ear has reduced compliance) or a flat curve without a peak, sometimes called a type B curve (figure 2). In a meta-analysis of seven studies, the sensitivity and specificity of a type B tympanogram for myringotomy-confirmed OME were 84 (95% CI 82-86) and 79 (95% CI 76-83) percent, respectively [2]. However, there was wide variation in individual studies (sensitivity ranged from 55 to 91 percent and specificity from 63 to 100 percent). Tympanometry is not reliable in the first four months after birth [93].
Tympanometry can be performed in the primary care setting to verify middle ear effusion that is suggested by pneumatic otoscopy. We suggest tympanometry to confirm middle ear effusion before referral to otolaryngology. Tympanometry also may suggest conductive hearing loss; children with flat tympanograms (figure 2) are likely to have hearing loss, although there is not a direct correlation.
Acoustic reflectometry with spectral wave analysis measures the reflection of sound from the tympanic membrane. Acoustic reflectometry provides a measure of the difference in sound intensity from the incident and reflected sound waves around the frequency of maximal nullification. When the tympanic membrane is normal, approximately one-half of the incident sound is reflected back to the device as a soft, broad-frequency echo; when there is fluid in the middle ear, the tympanic membrane is immobilized and the reflected sound is louder with a narrower spectrum [94]. In a meta-analysis of three studies, the sensitivity and specificity of acoustic reflectometry for myringotomy-confirmed OME were 64 and 80 percent, respectively [87].
●Artificial intelligence – Artificial intelligence and machine learning has the potential to help clinicians detect and diagnose of OME [95-97]. Experimental devices to detect OME have been developed but additional validation is necessary.
DIFFERENTIAL DIAGNOSIS — The major consideration in the differential diagnosis of OME is acute otitis media (AOM). AOM is defined by fluid in the middle ear accompanied by acute signs of illness and signs or symptoms of middle ear inflammation. The signs and symptoms of illness and inflammation differentiate AOM from OME. These include bulging of the tympanic membrane, ear pain, and/or fever. Bulging of the tympanic membrane effectively excludes OME. (See "Evaluation of earache in children".)
OME usually is asymptomatic. When present, the most common manifestation is mild and fluctuating hearing loss. Other conditions that cause hearing loss must also be considered and excluded before attributing hearing loss to OME. The differential diagnosis of hearing loss is discussed separately. (See "Hearing loss in children: Etiology" and "Hearing loss in children: Screening and evaluation".)
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: Acute otitis media, otitis media with effusion, and external otitis".)
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 5th to 6th 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 10th to 12th 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: Ear tubes (The Basics)")
●Beyond the Basics topic (see "Patient education: Ear infections (otitis media) in children (Beyond the Basics)")
SUMMARY
●Definition – Otitis media with effusion (OME) is defined as middle ear effusion without acute signs and symptoms of infection (picture 1). (See 'Terminology' above.)
●Epidemiology – OME is common, affecting 90 percent of children and 80 percent of ears by four years of age in the pre-pneumococcal conjugate vaccine era. Postvaccine era data suggest a decline in its prevalence. (See 'Epidemiology' above.)
●Clinical features
•Although most children with OME are asymptomatic, clinical manifestations may include hearing loss, a feeling of fullness in the ear, tinnitus, and balance problems. (See 'Clinical features' above.)
•OME is associated with a mild and fluctuating conductive hearing loss. The clinical significance of OME-associated hearing loss that resolves in <3 months is debated. (See 'Hearing loss' above.)
●Complications and sequelae – Complications and sequelae of OME that persists for ≥3 months (ie, chronic OME) include conductive hearing loss, myringosclerosis (picture 4), and, rarely, a tympanic membrane retraction pocket in which a cholesteatoma may eventually form (picture 5). (See 'Complications and sequelae' above.)
●Diagnosis – The diagnosis of OME is usually made with otoscopy demonstrating middle ear effusion (eg, impaired mobility of the tympanic membrane (movie 1), bubbles, air-fluid level (picture 1), and/or opacity of the tympanic membrane) without acute signs or symptoms of infection (including bulging (picture 3A-B) or marked erythema of the tympanic membrane, ear pain, fever). Tympanometry is often helpful, too. (See 'Diagnosis' above.)
●Management – The management of children with OME is discussed separately. (See "Otitis media with effusion (serous otitis media) in children: Management".)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Jerome Klein, MD, who contributed to an earlier version of this topic review.
