To diagnose ringworm, a physician will begin by performing a physical examination and compiling a thorough medical history of the patient.

Because other skin problems (e.g., atopic dermatitis, psoriasis) may cause symptoms similar to those of ringworm, certain tests may be required to definitively diagnosis ringworm. For example, the fungus that causes ringworm may appear fluorescent when examined under an ultraviolet light called a Wood’s lamp. In some cases, a sample of the patient’s skin at the affected site may be scraped off (or a small piece of hair or nails clipped off) and examined under a microscope. In other cases, the sample may be sent to a laboratory, where the sample will be cultured (procedure in which conditions are controlled to allow for the reproduction and growth of potential pathogens in a tissue sample). If the fungi that causes ringworm appears in that cultured sample, a patient can be diagnosed as having a ringworm infection.

Some ringworm infections may get better on their own without any treatment. Patients with minor symptoms also may be able to get rid of their ringworm with simple self-care measures. These include keeping the skin clean and dry, washing sheets and nightclothes daily during the period of infection, and using over-the-counter antifungal medications. However, patients should not use these medications without first consulting a physician.

In other cases, ringworm infections may require treatment with prescription medications such as antifungal creams or oral medications. Oral drugs may have to be taken for extended periods of time for treatment to be effective. In addition, oral medications may cause side effects in some patients, including gastrointestinal upset, rash and abnormal liver function. It typically takes about one month before medications completely remove the fungi causing ringworm from the body. It may take additional time for the affected area to heal properly and for hair to grow back.

Antibiotics may be prescribed to help treat bacterial skin infections that may occur as a complication of ringworm.