Not Found
Locations
Brought to you by

Find information on animal health topics, written for the veterinary professional.

Ringworm (Dermatophytosis) in Cats

By Karen A. Moriello, DVM, DACVD, Professor of Dermatology, Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison ; Thomas R. Klei, PhD, Boyd Professor and Associate Dean for Research and Advanced Studies, School of Veterinary Medicine and Louisiana Agriculture Experiment Station, Louisiana State University ; David Stiller, MS, PhD, Research Entomologist, Animal Disease Research Unit, U.S. Department of Agriculture, Agricultural Research Service, University of Idaho ; Stephen D. White, DVM, DACVD, Professor and Chief of Service, Dermatology, Veterinary Medical Teaching Hospital; Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis ; Michael W. Dryden, DVM, PhD, DACVM, University Distinguished Professor of Veterinary Parasitology, College of Veterinary Medicine, Kansas State University ; Carol S. Foil, DVM, MS, DACVD, Professor, Department of Veterinary Clinical Sciences, School of Veterinary Medicine ; Paul Gibbs, BVSc, PhD, FRCVS, Professor Emeritus, College of Veterinary Medicine, University of Florida ; John E. Lloyd, BS, PhD, Professor Emeritus of Entomology, University of Wyoming ; Bernard Mignon, DVM, PhD, DEVPC, Assistant Professor, Faculty of Veterinary Medicine, Department of Infectious and Parasitic Diseases, Parasitology and Parasitic Diseases, University of Liège ; Wayne Rosenkrantz, DVM, DACVD ; Patricia A. Talcott, MS, DVM, PhD, DABVT, Associate Professor, Department of Food Science and Toxicology, Holm Research Center, University of Idaho ; Alice E. Villalobos, DVM, DPNAP, Director;Director, Animal Oncology Consultation Service;Pawspice ; Patricia D. White, DVM, MS, DACVD

Also see professional content regarding dermatophytosis.

Ringworm is an infection of skin, hair, or claws caused by a type of fungus known as a dermatophyte. In cats, about 98% of ringworm cases are caused by the fungus Microsporum canis. The fungus is spread easily in the environment and often infects people.

The fungi spread to people primarily by contact with infected cats and contaminated objects such as furniture or grooming tools. Broken hairs with associated spores are important sources for spread of the disease. Contact does not always result in infection. Whether infection is established depends on the fungal species and on host factors, including age, health, condition of exposed skin surfaces, grooming habits, and nutrition. Infection leads to temporary resistance to reinfection. Under most circumstances, dermatophytes grow only in the dead cells of skin and hair, and infection stops on reaching living cells or inflamed tissue. As inflammation and host immunity develop, further spread of infection stops, but this process may take several weeks.

Infected cats can develop circular, bald, scaly patches with broken hairs in ring-like whirls. The center of the rings can regrow darker than normal hair. The most common areas for ringworm to occur are the face, ear tips, tail, and feet.

Veterinarians diagnose ringworm by fungal culture, examination with an ultraviolet lamp, and direct microscopic examination of hair or skin scale. Fungal culture of hairs and scrapings from the affected areas is the most accurate method. Direct microscopic examination of hairs or skin scrapings may allow early diagnosis.

Ringworm infections clear up without treatment, but cats with widespread ringworm are most often treated with anti-fungal medications prescribed by a veterinarian. Treatment with medicated shampoos can speed healing in some cases. Such treatments are not always effective, however. Your veterinarian can provide you with information about any treatment that may be appropriate for your pet and advise you regarding precautions you should take to avoid ringworm infection in yourself and members of your family.