, more often on exposed skin. In the United States, Trichophyton rubrum, T. mentagrophytes, and Microsporum canis are the most common causal organisms. People can become infected from contact with other people, animals, or soil. Variants of tinea corporis include tinea imbricata (caused by T. concentricum), bullous tinea corporis, tinea gladiatorum (seen in wrestlers), tinea incognito (atypical tinea resulting from topical steroid use), and Majocchi’s granuloma. Widespread tinea may be secondary to underlying immunodeficiency such as HIV/AIDS or treatment with topical or oral steroids.
The typical presentation of tinea corporis is scaly erythematous or hypopigmented annular patches with a raised border and central clearing. In tinea imbricata, which is more commonly seen in southeast Asia, India, and Central America, concentric circles and serpiginous plaques are present. Majocchi’s granuloma has a deeper involvement of fungus in the hair follicles, presenting with papules and pustules at the periphery of the patches. Lesions of tinea incognito may lack a scaly border and can be more widespread.
Diagnosis can be confirmed with a skin scraping and potassium hydroxide (KOH) staining, which will reveal septate and branching hyphae. Biopsy is often helpful, especially in tinea incognito. Classically, a “sandwich sign” is seen: hyphae between orthokeratosis and compact hyperkeratosis or parakeratosis. In this patient, a biopsy from the left hip revealed dermatophytosis, with PAS positive for organisms.
Localized lesions respond to topical antifungal creams such as azoles or topical terbinafine. More extensive tinea will often require a systemic antifungal with griseofulvin, terbinafine, itraconazole, or fluconazole. This patient responded to topical ketoconazole cream and oral terbinafine. A workup for underlying immunodeficiency was negative.
Dr. Bilu Martin provided this case and photo.
Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at MDedge.com/dermatology. To submit a case for possible publication, send an email to firstname.lastname@example.org.