Tinea cruris, a pruritic superficial fungal infection of the groin and adjacent skin, is the second most common clinical presentation for dermatophytosis. Tinea cruris is a common and important clinical problem that may, at times, be a diagnostic and therapeutic challenge.
Other Medscape articles on tinea infections include Tinea Barbae, Tinea Capitis, Tinea Corporis, Tinea Faciei, Tinea Nigra, Tinea Pedis, and Tinea Versicolor.
The most common etiologic agents for tinea cruris include Trichophyton rubrum and Epidermophyton floccosum; less commonly Trichophyton mentagrophytes and Trichophyton verrucosum are involved. Tinea cruris is a contagious infection transmitted by fomites, such as contaminated towels or hotel bedroom sheets, or by autoinoculation from a reservoir on the hands or feet (tinea manuum, tinea pedis, tinea unguium). The etiologic agents in tinea cruris produce keratinases, which allow invasion of the cornified cell layer of the epidermis. The host immune response may prevent deeper invasion. Risk factors for initial tinea cruris infection or reinfection include wearing tight-fitting or wet clothing or undergarments.
Dermatophytosis accounts for approximately 10-20% of all visits to dermatologists. 
Tinea cruris is 3 times more common in men than in women.
Adults are affected by tinea cruris much more commonly than are children. However, the prevalence of several risk factors for tinea cruris, such as obesity and diabetes mellitus, is rapidly increasing among adolescents. 
The prognosis of tinea cruris is excellent with appropriate diagnosis and treatment; however, recurrence is likely if the groin region is not kept dry.
No mortality is associated with tinea cruris. Associated pruritus leads to morbidity resulting from lichenification, secondary bacterial infection, and irritant and allergic contact dermatitis caused by topically applied medications.
Educate patients about the risks of sharing sheets and undergarments with others and about the need to keep the groin region dry (see Deterrence/Prevention).
For patient education resources, visit eMedicineHealth's Skin Conditions and Beauty Center. Also, see eMedicineHealth's patient education article Ringworm on Body.
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