Is tinea cruris (jock itch) a sexually transmitted infection?

　　Tinea cruris (jock itch) is a condition many people recognize as highly contagious and notoriously difficult to cure due to frequent recurrence. As a result, many mistakenly assume it is a sexually transmitted infection (STI). So—is tinea cruris an STI?

　　Is Tinea Cruris an STI?

　　No, tinea cruris is not an STI. It is a fungal skin infection.

　　Tinea cruris is not an STI. It is a dermatophyte infection affecting the inner thigh and groin area—specifically the skin of the inguinal region—and commonly involves the perineum, buttocks, and upper inner thighs. In its early stage, it manifests as well-demarcated erythematous plaques, with more pronounced inflammatory changes at the advancing margins than in the center (“active margin”). Mild fine scaling is typically present on the surface, accompanied by pruritus of varying intensity. Tinea cruris tends to occur during warm, humid seasons and is more common in men who sweat excessively—particularly those who are overweight and spend prolonged periods sitting. It can also spread from other infected sites on the body, such as tinea pedis (athlete’s foot) or tinea manuum (hand fungus), via autoinoculation to the groin area.

　　Treatment begins with wearing loose, breathable underwear and minimizing local sweating. Topical antifungal agents—such as ketoconazole, bifonazole, or terbinafine cream—are recommended. Consistent application is essential, as topical therapy carries a higher recurrence rate than oral treatment. Typically, treatment should continue for two weeks after complete resolution of lesions. Concurrently, examine other body areas—especially hands and feet—for signs of dermatophytosis. Oral antifungal therapy (e.g., itraconazole or terbinafine) may also be considered, particularly in recurrent or extensive cases.

　　The above addresses the question, “Is tinea cruris an STI?” We hope this information proves helpful.