Introduction

Despite its name, “ringworm” infection is not caused by a worm. It is a parasitic fungal infection of the superficial layers of the skin and hair fibers. In cats, almost all ringworm infections are caused by the fungus, Microsporum canis. This is a highly contagious fungus that can be spread between pets and even to people. If your cat is displaying any of the following symptoms of ringworm, make a quick appointment with your local veterinarian.

Symptoms of Ringworm

Kittens and long-haired breeds are more frequently clinically affected by ringworm than are older animals. There is no gender predisposition. In cats, the signs typically start as a circular pattern of hair loss (alopecia) or a generalized poor hair coat. Affected areas tend to become crusty, scaly, red, inflamed, irritated and itchy. Over time, the lesions may begin to spread. In some cases, the cat’s coat may feel greasy, or the owner may notice dandruff and dry, flaky skin.

Ringworm infection is typically very superficial and does little if any actual injury to affected cats. However, it is highly contagious and is commonly transmitted from pets to people, especially if the people are immunocompromised. Ringworm infection is underdiagnosed in companion cats.

This superficial fungal infection causes few if any traumatic clinical signs in affected animals. However, it needs to be managed carefully because it is extremely contagious. When they do appear, signs of dermatophyte infection in cats include circular regions of hair loss with varying degrees of crusting and scaly skin patches. Cats are less likely to become itchy than are dogs. In some cases, affected cats develop cutaneous bumps and pustules as well. Cats also often develop military dermatitis, chin acne and generalized seborrhea in addition to the classic circular lesions. Dermatophytosis is a zoonotic condition that tends to occur in immunocompromised individuals, especially in high density populations (shelters, boarding facilities) or in patients undergoing chemotherapy, on steroid medication or suffering from poor nutrition or inordinate stress. Ringworm is ubiquitous in the environment but is more prevalent in hot, humid climates.