(See also Overview of Fungal Skin Infections Overview of Fungal Skin Infections Fungi usually make their homes in moist areas of the body where skin surfaces meet: between the toes, in the genital area, and under the breasts. Common fungal skin infections are caused by... read more .)
Dermatophyte infections are sometimes called ringworm or tinea. Despite the name, a ringworm infection does not involve worms. The name arose because of the ring-shaped skin patches created by the infection.
Dermatophytes are molds (a type of fungi) that need the protein keratin for nutrition. Keratin is the structural material that makes up the outer layer of human skin. It is also the main structural material of hair and nails. To survive, dermatophytes must live on skin, hair, or nails (a nail infection is called tinea unguium or onychomycosis Onychomycosis Onychomycosis is a fungal infection of the nails. (See also Overview of Nail Disorders.) About 10% of people have onychomycosis, which most often affects the toenails rather than the fingernails... read more ).
Infection may occur almost anywhere on the skin, including the
A dermatophyte infection on one area of the body can cause a skin eruption to appear on another area of the body that is not infected (see Dermatophytid Reaction Dermatophytid Reaction A dermatophytid reaction is the body's reaction to a dermatophyte (fungal) infection and is a skin eruption that appears on an area of the body that is not the area where the infection first... read more ).
Dermatophyte infections in humans are caused by Epidermophyton, Microsporum, and Trichophyton. These organisms may inhabit a person permanently and never cause an infection. When they do cause an infection (resulting in ringworm or tinea), it is often because the affected area's blood supply is poor or because the person's immune system is suppressed (for example, by diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , cancer Overview of Cancer A cancer is an abnormal growth of cells (usually derived from a single abnormal cell). The cells have lost normal control mechanisms and thus are able to multiply continuously, invade nearby... read more , or HIV infection Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and can cause acquired immunodeficiency syndrome (AIDS). HIV is transmitted... read more ). Unlike candidiasis Candidiasis (Yeast Infection) Candidiasis is infection with the yeast Candida. Candidiasis tends to occur in moist areas of the skin. Candidiasis may cause rashes, scaling, itching, and swelling. Doctors examine the affected... read more , these fungal infections cannot infect internal organs or blood.
Symptoms of a dermatophyte infection vary depending on the location of the infection. Most often, there is little or no inflammation and the infected areas are mildly itchy with a scaling, slightly raised border. These patches can come and go intermittently. Occasionally, inflammation is more severe and suddenly causes large and small fluid-filled spots to appear (usually on the foot) or an inflamed, swollen patch on the scalp that sometimes oozes pus (kerion Kerion Scalp ringworm is a dermatophyte (fungal) infection of the scalp. Symptoms of tinea capitis include a dry patch of scale, a patch of hair loss, or both on the scalp. Doctors base the diagnosis... read more ).
Doctors can frequently identify a tinea infection by its appearance.
To confirm the diagnosis of tinea, doctors take skin scrapings Scrapings Doctors can identify many skin disorders simply by looking at the skin. A full skin examination includes examination of the scalp, nails, and mucous membranes. Sometimes the doctor uses a hand-held... read more and view them under a microscope. Doctors do a culture Culture Doctors can identify many skin disorders simply by looking at the skin. A full skin examination includes examination of the scalp, nails, and mucous membranes. Sometimes the doctor uses a hand-held... read more of the scrapings (the process of growing an organism in a laboratory for identification) only if the person has a scalp or nail infection. Identifying the type of fungus helps doctors choose the best treatment.
Treatment of tinea varies by site but always involves antifungal drugs that are applied to the affected area (topical) or are taken by mouth. (See also table Some Antifungal Drugs Applied to the Skin (Topical Drugs) Some Antifungal Drugs Applied to the Skin (Topical Drugs) Fungi usually make their homes in moist areas of the body where skin surfaces meet: between the toes, in the genital area, and under the breasts. Common fungal skin infections are caused by... read more .)
Corticosteroids may be given to relieve itching and inflammation.