Ringworm is a fungal infection of the skin, hair or nails. Despite its name, it is not caused by a worm. It can be treated with antifungal medicines, but the infection can return after treatment or fail to clear if the diagnosis or treatment is not appropriate.
One reason ringworm may return is that treatment was stopped too early. Antifungal medicines need to be used for the full period recommended by a healthcare professional or stated on the product instructions, even if the rash begins to improve. Stopping treatment prematurely can allow the infection to persist or reappear.
Reinfection is another possibility. Ringworm spreads easily, and the fungus can be transferred between parts of the body or between people. It can also spread through contaminated items and, in some cases, from infected animals. Keeping affected areas clean and dry, washing hands after touching an infected area and washing items that come into contact with the infection can help reduce the risk of spreading it.
A recurring rash should not automatically be assumed to be ringworm. Several skin conditions can resemble it, and healthcare providers may examine the affected skin or take a small sample for testing when necessary. Confirming the diagnosis can help ensure that the treatment is appropriate.
For uncomplicated ringworm on the skin, antifungal creams, ointments, lotions or other topical medicines can be effective. Some are available without a prescription, while other infections require prescription treatment. The choice depends partly on where the infection occurs and how extensive it is. Ringworm affecting the scalp or nails, for example, generally requires medical assessment and prescription treatment.
People should also be cautious about creams containing corticosteroids. The CDC advises against using steroid creams on ringworm or on an undiagnosed rash that could be ringworm because corticosteroids can worsen the infection and alter its appearance, making diagnosis more difficult.
If a rash does not improve with appropriate antifungal treatment, keeps returning or becomes more extensive, a healthcare professional should reassess it. The CDC notes that some emerging types of ringworm can be resistant to commonly used antifungal medicines, although these infections are not the explanation for every recurring rash.
Treatment also depends on the part of the body affected. Scalp ringworm, for instance, usually requires prescription antifungal medicine, while some infections on the skin can be treated with topical medicines. A healthcare professional can determine the appropriate treatment after assessing the infection.
The key point is that a recurring rash should not simply be treated repeatedly without considering whether the original diagnosis was correct, whether treatment was completed as directed, or whether reinfection is occurring. Medical assessment is particularly important when treatment fails to clear the infection or when the affected area is the scalp or nails.
