Symptoms & Treatment of Canine and Feline Ringworm: A C

There is a vast array of skin fungi species derived from animals, but only a few are responsible for causing tinea infections. These include Microsporum canis, Trichophyton mentagrophytes, and Trichophyton verrucosum, which are common fungi affecting the skin of cats and dogs. Unfortunately, the number of antifungal drugs available to veterinarians, as well as those approved for use, is limited. Moreover, systemic medications for pets are even rarer.

The Significance of Tinea Infections

Public health is greatly concerned about pet tinea infections, as the majority of skin fungi isolated from dogs and cats are zoonotic, meaning they can be transmitted between animals and humans. These fungi are highly resistant to the environment, surviving in dry conditions for up to 3 to 4 years and showing strong tolerance to general disinfectants. Dogs and cats infected with Microsporum canis can transmit the disease to their owners.

Epidemiology

The primary sources of infection are affected cats and dogs, along with contaminated objects. Transmission primarily occurs through direct contact between animals or through contaminated objects. External parasites, such as lice, fleas, flies, and mites, also play a significant role in the spread of the disease. Tinea infections can occur yearround, but they are most prevalent during warm and humid seasons. In most studies, Microsporum canis is the dominant species in cat tinea infections, accounting for up to 90% of cases.

Clinical Symptoms

The typical presentation of tinea infections is characterized by regular circular hair loss, redness, and thin scales. Itching is usually absent, although some cases may report itching. Lesions typically spread outward.

Ringworm in Cats

More than 90% of cases in cats are caused by Microsporum canis. Other species, including Trichophyton mentagrophytes and Trichophyton verrucosum, are also involved. Feral cats have a high incidence of infection, and the risk of human transmission is significant when these cats are adopted by pet owners. Lesions in young cats typically appear first on the nose bridge, ear flaps, and the outer edges of the ears, as well as on the distal ends of the legs and tails. In adult cats, lesions may be very small and require precise observation and testing.

Ringworm in Dogs

While Microsporum canis is the main cause of tinea infections in dogs, other skin fungi are more easily isolated from lesions in dogs than in cats. Dog ringworm often presents as patchy, hairless, and nonitchy lesions measuring 10 to 40 millimeters. In puppies, bacterial folliculitis and demodicosis may also occur simultaneously.

How to Treat

The immune response of the pet's body may be sufficient to control the spread of skin lesions caused by tinea infections, making tinea infections considered selflimiting diseases in animals with immune capability. However, it is recommended to use antifungal medications to shorten the duration of the infection and reduce the spread of the fungus to other animals and the environment. Systemic antifungal drugs can help accelerate the healing of the disease. Of course, for pets with chronic infections, it is essential to actively clean and disinfect their environment.

Factors to Consider in Treatment

1. For cats and dogs with tinea infections that do not respond to topical treatments alone, it is recommended to combine longterm systemic antifungal therapy with topical treatments, such as the new, highly effective antifungal oral solution Hanfu Xin (Itraconazole).

2. After general recovery, it is necessary to continue treatment for an additional 3 to 4 weeks after the fungal culture results are negative.

3. If the infection recurs after a few weeks of treatment, it is advisable to suspect:

① The owner did not provide treatment correctly, or the pet had poor absorption.

② Underlying diseases are interfering with the normal functioning of the immune system.

③ The environment was not properly disinfected.

④ There may have been a misdiagnosis.