Tinea Corporis

Tinea corporis (TC) is a superficial dermatophyte infection. Most common fungii causing TC are Trichophyton, Microsporum, and Epidermophyton.   T rubrum is the most common infectious agent causing Tenia corporis in the world (Trichophyton tonsurans is the most common dermatophyte to cause tinea capitis). Animals are common carriers of these dermatophytes.

Dermatophytes invade peripherally in a centrifugal pattern. The active border has an increased epidermal cell proliferation with scaling. A pruritic, circular plaque is characteristic sign.

Variants:
Majocchi granuloma: is a fungal infection in hair, hair follicles, and, often, the surrounding dermis, with an associated granulomatous reaction.

Tinea corporis gladiatorum: is an infection that spreads by skin-to-skin contact between wrestlers.

Tinea imbricata: is a form of TC common in Asia and has a characteristic imbricate appearance.

Tinea incognito: is TC with an altered presentation due to corticosteroid treatment.

Diagnosis is primarily clinical but can be confirmed by potassium hydroxide (KOH) examination of skin scrapings or cultures.

Treatment is accomplished using topical antifungals. Medication should be applied to the lesion and at least 2 cm beyond this area once or twice a day for at least 2 weeks. The topical azoles (eg, econazole, ketoconazole, clotrimazole, miconazole, oxiconazole, sulconazole, sertaconazole) inhibit the enzyme lanosterol 14-alpha-demethylase and are the most commonly used agents. Allylamines (eg, naftifine, terbinafine) inhibit squalene epoxidase and Ciclopirox olamine causes membrane instability and abnormal transport in fungii. These agents are uncommonly used.

Systemic therapy may be indicated for extensive TC especially in immunosuppressed individuals. Griseofulvin disrupts the microtubule mitotic spindle formation in metaphase, causing arrest of fungal cell mitosis. It is the systemic drug of choice for tinea corporis infections in children. Systemic azoles (eg, fluconazole, itraconazole, ketoconazole) function similar to the topical agents, causing cell membrane destruction and are used a back up.