Why Cholesteatoma Discharge is Foul-Smelling and Purulent
Cholesteatoma discharge is foul-smelling and purulent because the keratinized squamous epithelium creates an ideal environment for polymicrobial bacterial infection, with the accumulation of infected keratinous debris producing characteristic malodorous, purulent otorrhea. 1, 2
Pathophysiologic Mechanism
The characteristic discharge results from two interconnected processes:
Keratin Accumulation and Bacterial Colonization
Cholesteatoma consists of keratinized squamous epithelium that continuously produces and traps keratin masses within the temporal bone, creating an enclosed space where dead skin cells accumulate. 3, 4
This trapped keratinous debris becomes secondarily infected with polymicrobial bacterial flora, most commonly including H. influenzae, S. aureus, and P. aeruginosa. 5
The bacterial infection of this accumulated keratin produces the purulent component of the discharge, as the body's inflammatory response attempts to clear the infected material. 2, 6
Anaerobic Bacterial Metabolism
The foul odor specifically results from anaerobic bacterial metabolism within the poorly ventilated cholesteatoma sac, where bacteria break down the proteinaceous keratin debris and produce volatile sulfur compounds and other malodorous metabolites. 2, 7
The enclosed nature of cholesteatoma creates an ideal anaerobic environment that promotes growth of odor-producing bacteria, distinguishing it from other forms of otitis media. 6, 4
Clinical Presentation Pattern
All patients (100%) with extensive cholesteatoma present with foul-smelling, purulent ear discharge as the hallmark symptom, according to a 2022 case series. 2
The American Academy of Otolaryngology-Head and Neck Surgery characterizes cholesteatoma as typically presenting with foul-smelling, purulent ear discharge and hearing loss, and notes it is characteristically painless unless complications develop. 1
The discharge may be accompanied by visible white keratinous debris behind the tympanic membrane or within the ear canal, along with granulation tissue at sites of bony erosion. 1
Key Clinical Pitfall
Do not confuse cholesteatoma discharge with simple acute otitis media or ventilation tube-associated otorrhea—while tube-associated discharge may also have foul odor, it lacks the characteristic white keratinous debris and typically responds to topical antibiotics, whereas cholesteatoma requires surgical management. 5, 1