Ringworm (dermatophytosis) is an infection of the skin caused by a fungus (not a worm). Several fungi can cause it and are acquired from the soil or other animals (dogs, rodents). Dogs and cats are major sources for human cases of ringworm. Transmission is through direct contact with infected hair and scales, fungi in the environment (can be infective for up to 18 months), or contaminated objects (combs, brushes, clippers, bedding, transport crates). Young animals are more susceptible due to an immature immune system, however adults are often carriers showing no clinical signs. The typical ringworm lesion is a circular patch showing hair loss and scaliness. There are, however, many other clinical manifestations of patchy hair loss and skin inflammation. There are also many other skin conditions that mimic the typical ringworm lesions. Diagnosis is accomplished by using appropriate culture techniques. Other, less reliable, techniques include microscopic examination of hair shafts and examining for fluorescence under a special light. Treatment involves many facets. All efforts should be made to minimize human exposure. Latex gloves should be worn when treating animals or the environment. All animals should be carefully examined, isolated, and treated as needed. Topical treatment should be used to reduce ongoing environmental contamination and human exposure. Hair should be clipped from around the lesions and carefully disposed of. Miconazole or clotrimazole creams/sprays may be used on single lesions whereas enilconazole or lime sulfur dips are preferred for more extensive conditions. Systemic therapy involves oral griseofulvin. This medication can have side-effects and should not be used in pregnant animals. Another oral product, Program (lufenuron – a flea control product), has shown promise in treating ringworm. Environmental treatment is essential. All contact surfaces should be thoroughly vacuumed daily to remove contaminated hair and fungi. Surfaces, which will tolerate bleach, should be washed daily with a 1:10 solution of household bleach (be careful of bleach fumes causing respiratory problems). Heating and cooling vents should be vacuumed and disinfected. Destroy all bedding, rugs, brushes, combs, etc… Consult your veterinarian for accurate diagnosis and a treatment program.