Dermatophytosis of the external auditory meatus

Area of Science:

• Mycology
• Dermatology
• Otolaryngology

Background:

• Dermatophyte infections typically affect the skin, hair, and nails.
• External auditory canal infections are often bacterial or fungal, but dermatophytes are less commonly reported.
• Previous exposure to ringworm of the pinna is a potential risk factor.

Purpose of the Study:

• To investigate the prevalence and causative agents of dermatophyte infections in the external auditory meatus.
• To describe the clinical presentation and otoscopic findings of these infections.
• To establish a correlation between ear canal infections and ringworm of the pinna.

Main Methods:

• Retrospective analysis of 32 patient cases with suspected external auditory meatus infections.
• Clinical examination including otoscopy to assess the ear canal and tympanic membrane.
• Microscopic examination of ear scrapings using potassium hydroxide (KOH) mounts.
• Fungal culture to identify specific dermatophyte species.

Main Results:

• Thirty-two cases of dermatophyte infection in the external auditory meatus were identified.
• The most common causative agent was Trichophyton rubrum (29 cases), followed by Microsporum canis (2 cases) and Epidermophyton floccosum (1 case).
• Patients presented with mild symptoms like itching and cerumen accumulation, with intact tympanic membranes.

Conclusions:

• Dermatophyte infections, particularly by Trichophyton rubrum, can occur in the external auditory meatus.
• These infections are often associated with a history of or concurrent ringworm of the pinna.
• Otolaryngologists should consider dermatophyte infections in the differential diagnosis of external auditory canal pruritus and cerumen impaction.