Diagnosis: Majocchi granuloma
The diagnosis was Majocchi granuloma, a dermatophyte infection that causes rupture of the hair follicles and a secondary granulomatous process. The condition is often seen on the shaved legs of women. The most common dermatophyte is Trichophyton rubrum. Tinea barbae, a dermatophyte infection of the beard area, is most commonly caused by Trichophyton mentagrophytes var. mentagrophytes. In farmworkers, Trichophyton verrucosum should be suspected.1
Our differential diagnosis included bacterial folliculitis, sarcoidosis, pseudofolliculitis barbae, follicular mucinosis, and Majocchi granuloma. Bacterial folliculitis is common but rarely presents as indurated plaques in a nonimmunosuppressed patient. A granulomatous-appearing lesion in a black patient must always invoke sarcoidosis. Pseudofolliculitis barbae, an inflammatory process that mimics folliculitis, is commonly seen in the beard area of black men who shave. Follicular mucinosis can cause indurated plaques, but it often results in alopecia. These conditions are readily distinguishable on histopathologic examination.
In this case, histopathology revealed a granulomatous inflammatory process surrounding and obliterating the hair follicles. Under high power, fungal spores were seen in the dermis, but lack of bacteria ruled out bacterial folliculitis. In sarcoidosis, microscopic examination reveals numerous granulomas throughout the dermis without any signs of infection. Absence of mucinous degeneration ruled out follicular mucinosis.
Majocchi granuloma does not typically respond to topical antifungal therapy because the medication cannot penetrate deep enough to attack the offending dermatophyte. Micronized or ultramicronized oral griseofulvin in doses of 500-1,000 mg/day and 500-700 mg/day, respectively, can be used. The pediatric dosing is 20 mg/kg/day. Therapy should continue for four to six weeks. Other effective approaches include a two-month course of oral itraconazole 200 mg administered twice daily for one week each month and oral terbinafine 250 mg/day for two to three weeks.1
Our patient likely started with a superficial dermatophyte infestation. Follicular trauma from shaving allowed the or-ganism to enter the follicular structure. Two weeks of oral terbinafine 250 mg/day resulted in complete resolution.
Dr. Harting is assistant professor of dermatology at the University of Michigan Medical School in Ann Arbor.
1. Kelly P. Folliculitis and the follicular occlusion triad. In: Bolognia JL, Jorizzo JL, Rapini RP, eds. Dermatology. London, U.K.:Mosby;2003:553-566.