Ringworm in Cats

What Is Ringworm in Cats?

Ringworms or ringworm are the common names for dermatophytosis, a fungal infection that can affect a cat’s skin, hair, and nails.

The fungus, which feeds on dead cells, is not actually a worm. The name "ringworm" originated from the target-shaped lesion surrounded by a scaly ring seen in humans. It’s spread by direct skin-to-skin contact between people or between infected animals and people. 

For ringworm in cats, this fungal infection is typically presented through hair loss and scaly lesions.

Symptoms of Ringworm in Cats

Symptoms of ringworm in cats include:

• Thickened patches of skin

• Circular areas of hair loss (may be patchy)

• Broken and stubby hair

• Scaly or crusty skin

• Changes in fur or skin color

• Inflamed areas of skin

• Excessive grooming and scratching

• Red or gray, scaly lesions (typically on the skin of a cat’s head, chest, front legs, and spine)

• Dull fur

• Dandruff

• Rough, scaly, hardening of the base of the nails

• Distortion of the nails

• Nail infections (rare)

In some more severe cases of ringworm in cats, the skin lesions are raised and nodular. These are called granulomas and may frequently produce discharge. 

Many cats, especially longhaired breeds, may have ringworm without any symptoms at all. These cats are called asymptomatic carriers.

Asymptomatic cats may still infect other pets or humans. It’s important to note that even though these cats don’t look sick, they may be highly contagious. 

Causes of Ringworm in Cats

Ringworm in cats is spread through direct contact with the fungus. It may be passed by direct contact with an infected animal or person, the soil, or a contaminated surface. It’s rare—though possible—for ringworm to be spread through brushes, combs, and beds.

The fungal spore can survive and remain dormant on bedding, carpet, furniture, brushes, and/or other surfaces for up to 18 months.

Direct contact with a fungal spore causes infection, typically through open wounds (such as a scratch). However, immunosuppressed cats (cats with the decreased ability to develop a normal immune response) can get infected even without open skin.

Some predisposing factors for ringworm in cats include: 

• Age—Kittens and older cats with compromised immune systems are at a higher risk for infection. 

• Climate—Cats that live in warmer, more humid climates have a higher infection rate. 

• Care—Cats who live in a densely populated environment (such as an animal shelter) or receive poor nutrition are at a higher risk for infection due to the contagious and resistant nature of this fungus. 

• Health—Immune suppression can increase the risk of ringworm infection, especially in cats with feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV).

The period between exposure to the fungus and the development of symptoms is usually between seven to 14 days, though with some cases, three to four weeks may pass before symptoms appear.

How Veterinarians Diagnose Ringworm in Cats

There are several tests that can be performed to help diagnoses ringworm in cats. These include:

A wood’s light (fluorescent lamp) can be used to help identify some forms of ringworm.

Your veterinarian may also recommend looking for fungal spores under a microscope and culturing a sample of the fungus.

Difficult cases may require more advanced testing, such as PCR testing or skin biopsies.

Treatment for Ringworm in Cats

Treatment for ringworm in cats is usually a combination of medication applied to a cat’s skin and oral medication. Treatment lasts for a minimum of four to six weeks. In some cases, several months of therapy is required.

Ringworm cultures are performed after the start of treatment to determine if the infection is still present.

Treatment is typically continued until two consecutive negative ringworm cultures are obtained, usually two to four weeks apart. 

Topical Therapy

Topical treatment for ringworm in cats is directly applied to the skin. The treatment directly kills fungal spores, which is important in preventing environmental contamination and helpful in preventing contamination to other animals. Topical treatment will usually continue for several weeks or even months depending on your cat’s diagnosis. 

Oral Therapy

Oral therapy for ringworm in cats may be recommended for severe or difficult cases.

This treatment stops reproduction and spread of the fungal infection. Once treated, only the original fungus remains and can be removed with other treatment options.

Your veterinarian may prescribe one of the following: 

• Itraconazole 

• Terbinafine 

• Griseofulvin 

Side effects are possible when using antifungals and should be considered prior to starting therapy. Individual cats may have different reactions, but if therapy is discontinued too soon, the infection may recur.

Disinfecting The Environment

Infected cat hairs containing microscopic fungus spores may have been shed around your home.

Infection of other animals and humans, or reinfection of the affected cat, can occur from contact with the contaminated environment.

Ways to disinfect the environment include:

• Keeping all pets’ fur clipped short during treatment of the infection

• Careful hygiene to remove all pet hair from the environment

• Careful disinfection of areas frequented by the pets to attempt to kill the fungus in the environment

Recovery and Management of Ringworm in Cats

Commitment is the key to success in getting rid of ringworm in cats. Clean your home and test and isolate pets that have been in contact with the affected cat until they are found clear of infection. 

Keep your infected cat away from other animals, objects, surfaces, and family members. Wear gloves when handling your cat and wash your hands thoroughly afterward. 

Most cats who get appropriate treatment will recover from a ringworm infection, and you should see improvement within two to three weeks.

Symptoms may reoccur if the treatment is discontinued early or is not aggressive enough, or if there is an underlying condition affecting your cat’s immune system.

If an infection persists, your veterinarian may try alternative medications.

Prevention of Ringworm in Cats

Ringworm in cats can be prevented by:

• Keeping your pets healthy and current on their routine preventative care

• Avoiding crowding and stress

• Having new pets examined by a veterinarian before bringing them into the house and exposing them other people and pets. 

• Have any skin lesions checked promptly by a veterinarian to catch any issues as early as possible