Ringworm Symptoms and Treatment in Cats

Causes of Ringworm in Cats

Ringworm, despite the name, does not involve any worms. Ringworm is a fungal infection of the skin that affects different animals, including cats, dogs, rabbits, and humans. It is highly contagious and zoonotic, which means infected cats can transfer the fungus to humans. Because of this, ringworm in cats needs to be diagnosed and treated accordingly to help control the spread of the disease.

Ringworm infection is caused by a group of fungal organisms called dermatophytes. Several species of dermatophytes can cause ringworm but almost 98% of cases in cats are caused by Microsporum canis. This fungus is highly contagious, spreads easily from one infected individual to another, and can survive in the environment for a relatively long period.

How did my cat get ringworm?

Infection happens through direct contact with the fungus. Transmission usually occurs when a cat is in direct contact with an infected animal or object that has been contaminated with the spores of the fungus. Infected cats shed the spores from the fungus through broken hair strands falling off their skin.

However, direct contact does not automatically result in ringworm infection. The ability of the fungal spores to penetrate and cause an infection in a cat will also depend on the animal’s health condition, skin, immune system, age, and nutrition. Young and geriatric cats that are immunocompromised are at a greater risk of developing the infection compared to adult cats with relatively stable health conditions.

Dermatophytes infect primarily dead skin cells and damaged hair follicles, and infection usually stops spreading as soon as it reaches healthy skin cells or when the skin becomes inflamed. In healthy animals, the inflammatory reaction and immune response can help reduce or even eliminate infection, but this usually takes a few weeks.

Symptoms of Ringworm Infection in Cats

The most common clinical sign associated with ringworm infection in cats is hair loss or alopecia. The extent varies depending on the extent of the infection but most cases only present with localized patches of alopecia. The skin on the patches can appear crusty and scaly with broken hairs.

In some cases, the affected skin can appear red and inflamed with a distinct circular rash (hence the name ringworm) that is very itchy for cats. Excessive grooming and scratching may be seen in cats infected with ringworm. Occasionally, small pustules and bumps may form on the skin with hair loss, and secondary bacterial infection can occur.

How is ringworm diagnosed in cats?

When dealing with skin disorders in cats, effective treatment will highly depend on proper diagnosis. Identification of the fungal organism is needed to properly diagnose ringworm infection in cats. Diagnosis of dermatophytosis is done through different methods.

The most common way to diagnose ringworm is through microscopic examination of hair samples from infected animals. Fungal spores attached to the strands of broken hair are easily visible under the microscope and the presence is highly suggestive of ringworm infection.

Another tool used in diagnosing ringworm in cats is a Wood’s lamp - a piece of equipment that emits UV light to check for the presence of fungal spores. Though not all fungal spores fluoresce under UV light, the species mainly responsible for ringworm infection in cats will reflect and appear green when illuminated with a Wood’s lamp in a dark room. The fluorescence of a cat’s skin and fur under a Wood’s lamp is highly indicative of dermatophytosis.

These methods, though effective in detecting the presence of fungal spores, do not technically provide a definitive diagnosis. Identification is done through fungal isolation and culture. Proper identification of Microsporum canis from the samples obtained is definitive of dermatophytosis or ringworm infection in cats.

Recommended Treatment for Ringworm Infection in Cats

Most cases of ringworm infection in cats are localized and can easily be treated with topical antifungal medications. Depending on the number of skin lesions, using a medicated shampoo or an antifungal cream is often enough to clear the infection. Treatment usually lasts for a few weeks and is often extended even after lesions have cleared up to reduce the risks of reinfection.

In some cats, ringworm infection is self-limiting and resolves on its own through the host’s own immune response. However, this process usually takes a few weeks before a complete resolution is reached. In cats with severe and generalized ringworm infection, systemic oral antifungals may be necessary to effectively treat the disorder.

Systemic antifungals can potentially cause serious liver side effects and should only be used if necessary. A veterinarian can thoroughly assess the severity of the ringworm infection and decide if systemic antifungal treatment is needed or the use of topical ones is enough to facilitate effective treatment.

Can we prevent ringworm infection in cats?

Since ringworm is primarily transmitted through contact with infected animals and contaminated surfaces and objects, the spread of the infection can be controlled by proper isolation of infected animals, especially in a multi-cat household. Since ringworm infection is zoonotic and can be transferred from an infected cat to humans, it’s important to isolate and temporarily quarantine any infected cats at home while undergoing treatment.

Thorough decontamination of areas and objects that may have been contaminated with fungal spores will also help control the transmission of infection. For most households, this is often sufficient in containing the infection and preventing transmission between individuals.

Recently, a vaccine is being studied that protects animals against the Microsporum canis species of fungus that commonly causes dermatophytosis. Since, in cats, ringworm infections are mostly caused by this species, regular vaccination may be highly effective in protecting them against ringworm infection.

Read more:

Common Skin Parasites in Cats

Ear Mites in Cats

Common Intestinal Parasites in Cats

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