Tinea Corporis (Body Ringworm)

Tinea corporis is a dermatophyte infection of glabrous (non-hair-bearing) skin of the trunk and extremities, classically caused by Trichophyton rubrum, T. mentagrophytes, T. tonsurans, Microsporum canis, and Epidermophyton floccosum. Transmission occurs through direct contact with infected humans (anthropophilic), animals (zoophilic, particularly cats and cattle), or soil (geophilic), as well as fomites such as towels, gym mats, and shared clothing.

Lesions begin as small erythematous papules that expand centrifugally to form annular plaques with raised scaly borders and central clearing, often pruritic. Variants include tinea incognito (modified by topical steroids with diminished scaling and atypical borders), majocchi granuloma (deep follicular invasion in immunocompromised or shaved areas), and bullous tinea. Diagnosis is supported by potassium hydroxide (KOH) preparation showing branching septate hyphae and confirmed by fungal culture or PCR when needed.

Topical azoles (clotrimazole, ketoconazole, miconazole), allylamines (terbinafine, butenafine), or ciclopirox applied twice daily for 2-4 weeks are first-line for limited disease; terbinafine has the highest cure rates. Oral terbinafine 250 mg daily for 2-4 weeks, itraconazole 200 mg daily for 1-2 weeks, or fluconazole 150-300 mg weekly is required for extensive disease, Majocchi granuloma, and immunocompromised hosts. Treatment of pets and family contacts and laundering of fomites reduce reinfection.