Symptoms of Ringworm in Cats

Ringworm in cats, or dermatophytosis, is a fungal infection that affects the hair, skin and nails and can lead to hair loss. Ringworm is the most common contagious skin infection found in cats. Symptoms include skin lesions, pustules and crustiness. The fungus that causes ringworm can survive for long periods of time in the open, so cats can catch ringworm just from being in an environment where other cats have been.

Causes and Transmission of Ringworm

There are several different types of fungus that can cause ringworm, but most cases are caused by Microsporum canis, Microsporum gypseum or Trichophyton species. The fungus can be spread by contact with the infected animal, or with that animal's living quarters, bedding or grooming equipment. The ringworm fungus can live in the environment for up to two years, and thrives in warm, humid locations. Ringworm is contagious to both dogs and humans.

Cats can carry the fungus without showing any symptoms of infection. In fact, most cats are exposed to ringworm fungus in veterinary clinics and boarding kennels, where the spores can remain viable in the environment for long periods of time. Healthy adult cats often don't develop symptoms of infection. Kittens and cats with suppressed immune systems may develop symptoms of ringworm infection.

Symptoms of Ringworm Infection

Cats with ringworm often develop small skin lesions. These lesions are crusty in appearance and devoid of hair. Small pustules may appear in the lesion. The lesions may start off small in size and grow larger over time.

Lesions appear most frequently on the head, ears and tail. In more severe ringworm infections, the fungus can spread over the lips, nose, face and chin. In the most severe cases, the fungus spreads over the entire body, giving the skin a greasy, scaly appearance and leading to widespread hair loss.

The first sign of ringworm infection is excessive shedding. Excessive hairballs may occur if the fungal infection is widespread. Depending on the extent, hair loss may be quite severe.

Ringworm lesions may become itchy and irritated, causing the affected cat to scratch. Ringworm infection can also occur in the nails, deforming them.

Diagnoses and Treatment of Ringworm

Testing is required to diagnose ringworm infection, as its symptoms are similar to those of many other skin diseases. The most reliable test involves removing a sample of scaly skin from the lesion and performing a fungal culture.

Ringworm infection is treated with topical anti-fungal cream. In more severe cases, a combination of oral and topical medications may be required. Oral anti-fungal medications are generally used for those with severely widespread lesions, long hair or deformed nails. For the most severe cases of ringworm infection, lime sulfur dips are the topical medication of choice.

Effective ringworm control is necessary to prevent reinfection. Spores are carried on the air, so vacuuming and damp mopping are recommended to clean them from the environment. Carpets should be steam cleaned and heating and cooling ducts professionally vacuumed. Furnishings, linen and upholstery should be cleaned. Wood and metal should be repainted, and all surfaces should be cleaned with a 1:10 bleach solution.