| Bacterial causes |
| Haemophilus influenzae type B (Hib) |
| H. influenzae types A and F, and nontypeable strains |
| Haemophilus parinfluenzae |
| Streptococcus pneumoniae |
| Staphylococcus aureus (methicillin susceptible and methicillin resistant) |
| Beta-hemolytic streptococci: Groups A, B, C, F, G |
| Pasteurella multocida |
| Moraxella catarrhalis |
| Klebsiella pneumoniae |
| Neisseria meningitidis and other Neisseria species |
| Escherichia coli |
| Enterobacter cloacae |
| Pseudomonas aeruginosa* |
| Viral causes¶ |
| Herpes simplex virus type 1 |
| Varicella zoster virus |
| Parainfluenza virus type 3 |
| Influenza B viruses |
| Epstein-Barr virus |
| SARS-CoV-2 |
| HIV |
| Fungal causes |
| Candida albicans* |
SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; HIV: human immunodeficiency virus.
* Candidal and pseudomonal epiglottitis usually occur in immunocompromised patients.
¶ Epiglottitis may result from bacterial superinfection.