Background: Trichomycosis axillaris (TA) is the most common superficial bacterial infection of hair shaft, mainly of axillary hairs and producing pigmented concretions around hair shaft caused by various species of corynebacteria.
Aims and objectives: To study the clinical characteristics, Wood's lamp findings, dermoscopic features, microbiological and histopathological aspects of TA, and frequency of the corynebacterial triad.
Patients and methods: A descriptive cross-sectional study of 78 patients diagnosed with TA was done in a tertiary care center in South India from July 2021 to December 2022.
Results: The mean age was 29 years. Among 78 patients, 94.8% (74) were males. Nineteen (47.5%) patients were asymptomatic, and others had malodor, staining of clothes, and itching. The flava variant was the most common [96.15% (75 patients)] with yellow fluorescence in 96.15% (75 patients) on Wood's lamp. The brown variant, seen in 3.85% (3 patients), had no fluorescence. On histopathological staining with hematoxylin and eosin, Gram's, Periodic Acid-Schiff, Alcian Blue-Periodic Acid-Schiff, and Hales colloidal iron, all stained bacilli except Hale's colloidal iron. Bacteriological culture was positive in only 34 (43.59%) cases; 29 (85.29%) grew a single organism, and five (14.71%) grew two organisms. The majority, 64.71% (22 samples), grew diphtheroids, and 41.17% (14 samples) grew Staphylococcus. Four (5.13%) patients had corynebacterial triad.
Limitations: Cross-sectional study, small sample size, and poor culture yield.
Conclusion: TA involves young males from rural areas, commonly in summer. The flava variant is the most common. No distinct species of bacteria (diphtheroids and staphylococci) could be related to its cause.
Keywords: Dermoscopy; histopathology; microbiological; trichomycosis axillaris.
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