The KOH Test for Candida albicans, also known as a potassium hydroxide preparation or KOH prep, is a quick fungal test to differentiate dermatophytes and Candida albicans symptoms from other skin disorders like psoriasis and eczema. Dermatophytes are a type of fungus that invades the top layer of the skin, hair, or nails. There are three genera of fungi commonly implicated: Trichophyton (found in skin, nail, and hair infections), Epidermophyton (skin and nail infections), and Microsporum (skin and hair infections). Dermatophytes produce an infection commonly known as ringworm or tinea. It can appear as "jock itch" in the groin or inner thighs (tinea cruris); on the scalp and hair (tinea capitis) resulting in brittle hair shafts that fall out easily. Tinea unguium affects the nails and athlete's foot (tinea pedis) affects the feet. Tinea versicolor refers to a fungal infection of the skin caused by Malassezia furfur. It appears anywhere on the skin and produces red or gray, scaly patches of itchy skin. Deeper infections may be discoloured, ulcerative and purulent. A Candida yeast infection can also be identified by a KOH test by taking scrapings from the mouth (oral thrush), vagina (vaginitis) and skin (candidiasis). There are over 40 different fungus species known to cause disease in humans, of which Candida albicans is the most common and most frequently tested for.