Scalp ringworm is a dermatophyte (fungal) infection of the scalp.
Tinea capitis is a type of dermatophytosis (see see Overview of Dermatophytoses (Ringworm, Tinea)). In the United States, tinea capitis is primarily caused by Trichophyton. Tinea capitis is highly contagious and is common among children (see see Rashes in Children).
Tinea capitis may cause a dry scaly rash that may be somewhat itchy, a patch of hair loss, or both. One type of fungus causes "black dot" ringworm, in which hair shafts break at the scalp surface. Another type of fungus causes "gray patch" ringworm, in which hair shafts break above the surface, leaving short stubs. Tinea capitis may sometimes cause flaking that resembles dandruff.
A dermatophyte infection occasionally causes a kerion, which is a large, painful, inflamed, swollen patch on the scalp that sometimes oozes pus. A kerion may have blisters and crusting and can look like an abscess (a pocket of pus). A kerion is caused by an immune system reaction to the fungus and may result in scarring hair loss.
Tinea capitis is diagnosed by its appearance and the results of an examination of a sample of plucked hairs or of hairs and scale from the scalp. Doctors examine the samples under a microscope. Sometimes a type of ultraviolet light is shined on the samples to distinguish the type of fungus. Doctors may also do a culture (the process of growing an organism in a laboratory for identification) of the samples.
In children, treatment involves an antifungal drug called griseofulvin taken by mouth for 4 to 6 weeks. Terbinafine is an alternative drug for children. An antifungal cream should be applied to the scalp to prevent spread, especially to other children, until the tinea capitis is cured. Prescription-strength selenium sulfide shampoo should also be used at least twice a week. Children may attend school during treatment.
In adults, treatment is with the antifungal drug terbinafine or itraconazole taken by mouth. How long treatment is needed depends on the drug used.
For severely inflamed areas and for a kerion, doctors may prescribe a short course of a corticosteroid such as prednisone taken by mouth to lessen symptoms and perhaps reduce the chance of scarring.
Last full review/revision June 2013 by Denise M Aaron, MD