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Tinea Cruris (Jock Itch)


Denise M. Aaron

, MD, Dartmouth-Hitchcock Medical Center

Last full review/revision Feb 2020| Content last modified Feb 2020
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Tinea cruris is a dermatophyte infection of the groin. Diagnosis is by clinical appearance and by potassium hydroxide wet mount. Treatment is with topical antifungals.

Tinea cruris is a dermatophytosis that is commonly caused by Trichophyton rubrum or T. mentagrophytes. The primary risk factors are associated with a moist environment (ie, warm weather, wet and restrictive clothing, obesity causing constant apposition of skinfolds). Men are affected more than women because of apposition of the scrotum and thigh.

Typically, a pruritic, ringed lesion extends from the crural fold over the adjacent upper inner thigh. Infection may be bilateral. Lesions may be complicated by maceration, miliaria, secondary bacterial or candidal infection, and reactions to treatment. In addition, scratch dermatitis and lichenification can occur. Recurrence is common because fungi may repeatedly infect susceptible people or people with onychomycosis or tinea pedis, which can serve as a dermatophyte reservoir. Flare-ups occur more often during summer.

Diagnosis of Tinea Cruris

  • Clinical evaluation

  • Potassium hydroxide wet mount

Scrotal involvement is usually absent or slight; by contrast, the scrotum is often inflamed in candidal intertrigo or lichen simplex chronicus. If the appearance is not diagnostic, a potassium hydroxide wet mount is helpful.

Differential diagnosis of tinea cruris includes

Treatment of Tinea Cruris

  • Topical antifungal cream, lotion, or gel

Antifungal choices include terbinafine, miconazole, clotrimazole, ketoconazole, econazole, naftifine, and (uncommonly) ciclopirox applied 2 times a day for 10 to 14 days.

Itraconazole 200 mg orally once a day or terbinafine 250 mg orally once a day for 3 to 6 weeks may be needed in patients who have refractory, inflammatory, or widespread infections.

Key Points about Tinea Cruris

  • Suspect tinea cruris when pruritic, ringed lesions extend from the crural fold over the adjacent upper inner thigh, particularly in obese patients or men.

  • Topical terbinafine, miconazole, clotrimazole, ketoconazole, econazole, or naftifine 2 times a day for 10 to 14 days is usually effective.

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