[Written by a Veterinarian] What is Feline Dermatophytosis? Causes, Symptoms, Treatment, and Prevention Methods You Can Implement at Home

Feline dermatophytosis is a skin infection caused by fungi (mold). It can be seen in kittens with low immunity and can also infect humans. This article will explain feline dermatophytosis in detail.

What is Feline Dermatophytosis?

What is Dermatophytosis (Fungal Infection)?

Dermatophytosis is an infection of the skin caused by fungi, commonly known as mold.

Athlete's foot is a well-known fungal infection in humans. Fungi themselves are naturally present on healthy skin and are part of the normal flora. In a healthy state, the skin's barrier function prevents fungal invasion, so no symptoms appear. However, when the body's immunity decreases, the skin's barrier function weakens, allowing fungi to invade the body. This is dermatophytosis.

Why it is also called "Ringworm"

Fungal infections in cats are caused by dermatophytes, Candida, and Malassezia. Fungal infections affecting the skin are primarily caused by dermatophytes, which is why they are also called dermatophytosis or ringworm.

Differences from other skin diseases

Fungal skin infections can manifest with skin lesions such as hair loss, itching, and crust formation, which are also seen in other skin diseases. In cases of dermatophytosis, circular hair loss and scabs may appear in the affected area. However, dermatophytosis cannot be diagnosed solely by its appearance.

Main Symptoms and Identification of Feline Dermatophytosis

Circular hair loss, scabs, redness, itching

Dermatophytosis often begins with circular hair loss, which gradually spreads. The affected skin may become red, and dandruff or scabs can form. Itching is usually not very severe.

Areas that require particular attention

Fungal skin infections are often seen on the face and ears. However, in kittens or senior cats with weakened immune systems, or cats with underlying medical conditions, it can affect the entire body.

Beware of asymptomatic infection where symptoms may not appear easily

Some cats can be infected with dermatophytosis without showing any symptoms (asymptomatic infection). Even without symptoms, hair loss may occur after a few days. Asymptomatic carriers can spread fungal spores, acting as a source of infection.

Causes and Transmission Routes of Feline Dermatophytosis

Types of dermatophytes

Most cases of feline dermatophytosis are caused by the fungus Microsporum canis. Other causes can include Microsporum gypseum and Trichophyton mentagrophytes.

Infection from contact with other cats, environment, and pet supplies

The fungi that cause dermatophytosis adhere to hair and dander, and even after shedding, they remain infectious for a long time. These fungi can be transmitted directly from an infected cat, or indirectly via carpets or cat supplies. Even if the fungi come into contact with the skin, infection will not occur if the host's immune system is strong.

Note that it is a "zoonotic disease" that can infect humans.

Feline dermatophytosis is not just a problem for cats; it can also infect humans and other animals.

In humans, it typically appears as circular skin inflammation on the arms, known as "ringworm." Once infected, it can take a long time to completely heal, and there's a risk of new infections to other animals.

The author has also been infected with dermatophytosis multiple times and is currently undergoing treatment. Even with infection control measures like wearing gloves and gowns during examinations, it's still a contagious disease that can spread if immunity is low, so caution is necessary.

Diagnosis and Treatment (at the veterinary clinic)

Wood's lamp examination, hair examination, culture test

Among dermatophytes, Microsporum canis fluoresces under a special ultraviolet light called a Wood's lamp. Additionally, if hair from the affected area is plucked and examined under a microscope, fungal hyphae and spores can be observed within the hair. By culturing this hair on a medium, the type of causative fungus can be identified.
Since the skin symptoms of dermatophytosis resemble those of other skin conditions, various dermatological examinations may be performed to rule out other diseases.

Antifungal drugs (topical/oral), medicated shampoo

Antifungal medications are used to treat dermatophytosis. For localized infections or mild symptoms, topical antifungal creams are used. If the infection has spread throughout the body or topical medications are ineffective, oral antifungal medications are prescribed.
If the cat can be bathed, frequent shampooing with an antifungal shampoo is recommended. Since fungi infect the hair, clipping the hair may also be necessary.

Continued treatment is crucial as complete recovery can take time.

Complete recovery can take anywhere from two weeks to several months from the start of treatment. Furthermore, even after apparent recovery, re-infection can occur from fungi attached to other hair or shed hair. The infectivity of fungi remaining in shed hair is believed to last for over a year in some cases. Therefore, even if symptoms disappear, do not stop treatment on your own and continue until your veterinarian gives permission.

Tips for Prevention and Care at Home

Infection control

When adopting a new cat (especially a stray or rescue cat), it's best to assume they might have a fungal infection.

Wash cat items frequently if they are washable. For non-washable items, wipe them down with diluted bleach. Since fungi thrive in moist environments, thorough drying is also important.
Since it can also infect humans, be sure to wash your hands after touching your cat and try to bathe daily.

Creating an environment to reduce stress and maintain immunity

Fungi are blocked by the skin barrier if the immune system is strong. Cats susceptible to dermatophytosis are kittens and senior cats with weakened immune systems, or cats with underlying medical conditions.
To maintain immunity, it's important to live in a low-stress environment. Keep the room temperature appropriate, ensure enough space for exercise, and provide places to rest or hide.

Important points for multi-cat households

In multi-cat households, if one cat gets infected, others will also get infected. Infected cats must be completely isolated from other cats to prevent contact. Other cats may also develop symptoms after some time, so regularly check them for any skin abnormalities.

If you notice any abnormalities in your cat's skin, visit the vet immediately.

Risk of worsening due to neglect and infection to family members

Dermatophytosis will not heal on its own if left untreated. Treatment with antifungal medication is necessary. Without appropriate treatment, it can spread throughout the body.
Since fungi embed themselves in hair, shed hair can also be a source of infection. Shed hair can remain infectious for a long time, posing a risk of reinfection. Without treatment, infectious hair will constantly be shed. Hair loss and skin lesions can also infect humans.

Early consultation is important as it is difficult to distinguish from other skin diseases.

Fungal skin infections often present with hair loss and scabs, which are also common in other skin inflammations, making a diagnosis based solely on appearance difficult. Fungi are highly contagious, so they can unknowingly spread to others. In some cases, owners have applied steroid creams on their own, which worsened the fungal infection. Steroids can exacerbate fungal infections, so never use medication without veterinary advice. If you notice hair loss on your cat's skin, seek veterinary attention immediately.

Summary

Feline dermatophytosis is a common skin condition often seen in kittens, rescue cats, and senior cats. It often starts with hair loss, but can be overlooked due to minimal itching. However, it is highly contagious and can infect humans and other animals, making early treatment and infection prevention crucial.

Treatment can be lengthy, so continue treatment and environmental hygiene until your veterinarian gives permission. And if you, the owner, develop any skin symptoms, please consult a dermatologist.