Tinea of vellus hair in extensive tinea incognito

บทคัดย่อ

Tinea of vellus hair is defined as dermatophytic infection of the vellus hair.  Although it is the infection of glabrous skin, its prognosis is similar to tinea capitis and those patients should receive systemic antifungal therapy since the beginning of the correct diagnosis. Both tinea of vellus hair and tinea incognito can occur simultaneously due to the common sequelae of prolonged use of either topical corticosteroids or systemic corticosteroids. In this article we reported a case of dermatophyte infection in a patient who had been erroneously treated with topical and systemic corticosteroids which led to the alteration of the clinical lesions and caused this patient to have side effects of unnecessary corticosteroids use. Skin biopsy shows fungal elements in the stratum corneum which correlates to the microscopic examination from skin scraping showing septate hyphae and spores around the vellus hair shaft. The fungal culture was positive for Trichophyton mentagrophytes var mentagrophytes which supports the overall diagnosis of tinea incognito with tinea of vellus hair.