Fungal infections are common afflictions caused by organisms known as dermatophytes, which attack the keratin in skin, nails, and hair. These primarily only affect the outer layer of skin and are named based on the locations on the body where they are found, but they may be found deeper in the skin for some victims. Otherwise healthy individuals can get these infections, but those with weaker immune may be more prone. Common areas of infection include the scalp, where it is known as tinea capitis; the feet, as tinea pedis; the groin, as tinea cruris; and other areas, as tinea corporis. While these different infections will be discussed in turn, it is important to note that for all tinea infections, a steroid-based treatment such as a hydrocortisone cream will worsen the problem.
Tinea Capitis (Scalp)
These infections are found primarily in children. It is unlikely for an adult to have tinea capitis unless the individual has a weak or suppressed immune system.
There are three forms of tinea capitis: “black dot”, “gray patch”, and favus. “Black dot” tinea capitis is the predominant form in the U.S., whereas “gray patch” and favus may be contracted in other areas where infection is found.
The most common form found in the United States, it is mostly an infection in children and sometimes the elderly, although adult cases may be seen. African-American children are particularly susceptible, although the exact cause is not known for sure. It may be passed from child to child, including through shared items such as hair brushes. Black dot tinea capitis will cause red, scaly lesions (one or many) and may not be noticed until the hairs break off and cause bald spots.
The epidemic form has since been eliminated in the U.S., but isolated cases can be caught from cats and dogs. The infection causes a circular scaly red patch on the scalp that begins to grow outward. When the swelling decreases, the hairs within the area break off.
This form is generally only found in China, Nigeria, and Iran today. Red patches on the scalp will turn into cup-shaped yellow crusts that may eventually fuse together and cover the balding skin. Contact is usually insufficient for passing on the infection– prolonged exposure is necessary.
Treatment for all three forms are the same. Applying treatments to the skin are ineffective; oral medicine is typically given. The most common drug for children is griseofulvin, but terbinafine, itraconazole, and fluconazole may also be used. Regardless of the type used, treatment can span several weeks with numerous visits to the doctor for status updates. For all individuals with an infection, check with a doctor to see if a weak or suppressed immune system is a concern.
Prepared by Kevin Lin, UT-Austin Pre-Medical Student
Reviewed by Muhammad Emran, MD