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Dermatophytosis in Cats
Dermatophytosis is the medical term for a fungal infection affecting the skin, hair, and/or nails (claws) of cats. The most common of these parasites are 'Microsporum Canis Trichophyton mentagrophytes, and Microsporum gypseum (Commonly Known as Ringworm).This disease occurs in dogs and other mammals, and, in cats, these infections are more common in long-haired breeds than short-haired breeds.
Ringworm in Cats is diagnosed largely with kittens and younger cats rather than in older adults.Ringworn can affect both dogs and cats, and if you would like to learn more about how ringworm or 'Dermatophytosis' affects dogs please visit the PetMD pet health library.
Symptoms and Types of Ringworm
Symptoms affecting your cats can include a collection of dead skin cells.
This cell collection can lead to: dandruff (scales); poor hair coat with irritated and reddened skin (erythema); darkened skin (hyperpigmentation); itchiness (pruritus); and hair loss (alopecia), which may be patchy or circular. The classic sign of circular hair loss is most commonly seen in cats.
Some other symptoms of Ringworm are raised, rounded, knotty (nodular) lesions known as granulomatous lesions, or boils. Granulomas are raised nodular lesions that frequently ooze (kerions), as a result of ringworm infection. There may also be inflammation of the the folds of skin bordering the nail and other skin and nail folds - medically referred to as paronychia.
Even though these are some of the symptoms of ringworm in cats, some of those infected may be asymptomatic. These types of cats infected with ringworm are classified as inapparent carriers -- harboring the disease-causing fungus, but presenting no visible signs of the condition. But make sure to remember even though they do not look sick, these cats are contagious to humans or other animals.
Ringworm is by far the most common cause of dermatophytosis in cats. The amounts of cases vary due your geographical location. Environments that are densely populated with animals (for example, in a cattery or animal shelter), or where there is poor nutrition, poor management practices, and lack of adequate quarantine period, will also increase risk of infection.
Immunocompromising diseases, or immunosuppressive medications (factors that decrease the body's ability to develop a normal immune response) can raise the likelihood that your cat will be at risk of a fungal infection of the skin, hair, and/or nails, as well as increase the potential for a more severe infection.
Your veterinarian will perform a fungal culture of skin clippings, a microscopic examination of a sample of hair, and possibly a skin biopsy.
Most cats can be treated for ringworm on an outpatient basis, but quarantine procedures should be considered due to the infective and zoonotic (transmittable to humans) nature of some types of dermatophytosis. If your veterinarian needs to prescribe anti-fungal medications, the use of an Elizabethan collar (a wide collar placed around the neck) is recommended to prevent ingestion of anti-fungal medications applied to your cat's skin.
Living and Management
A fungal culture is the only way of truly monitoring your cat's treatment. Many animals will improve and look like they are recovering with treatment, but they may remain fungal culture positive. It is advisable to repeat fungal cultures toward the end of treatment, and continue treatment until at least one culture result is negative. In resistant cases, fungal cultures may be repeated on a weekly basis, and treatment continued until two to three consecutive negative results are obtained. Complete blood counts should be performed weekly or biweekly for cats receiving griseofulvin, an anti-fungous antibiotic. Also, blood work to monitor liver changes may be indicated for cats receiving ketoconazole or itraconazole, two types of anti-fungal medications.
To prevent reinfection from other animals, the use of a quarantine period and fungal (dermatophyte) cultures of all animals living in the household are necessary. Treatment of exposed animals should be considered to prevent repeated development of infection. The possibility of rodents aiding in the spread of the disease should also be considered. If you suspect that your cat has access to rodents, or that rodents are in your immediate environment, it is highly advised that you take the necessary steps to eliminate the pests.