Tinea cruris (“crotch rot”) is a fungal infection of the skin in the groin. The fungi usually come from the Trichophyton, Microsporum and Epidermophyton families and are caught by close contact (eg. sexual) with an infected person, or in babies may be due to wet nappies or sweaty skin. Infection is more common in men than women, has a peak incidence in the 20s and 30s, and tends to occur more in summer and with exercise.
A red, scaly rash spreads out from the skin folds in the groin to cover the inside of the thighs, the lower abdomen and the buttocks. It is often itchy and feels constantly uncomfortable. A secondary bacterial infection of damaged skin is possible. The diagnosis proved by taking a skin scraping and examining it under a microscope for fungal spores.
Antifungal creams, ointments, lotions and tinctures are usually effective. Antifungal tablets are available for more serious infections, but sometimes they are very slow to work, and may need to be taken for up to six months.
The prognosis is good with proper treatment, but recurrences are common.