Dermatophytosis, Microsporum canis, Trichophyton mentagrophyets, Microsporum gypseum.
Otherwise know as Ringworm.
Ringworm can affect dogs, cats, humans, horses, and cows. Ringworm can be transmitted between humans and animals but it is uncommon. Ringworm is a fungal disease. It is called ringworm because of the pattern of lesions it produces; circular areas of hair loss with red, raised outer rims. This ring is caused by hair follicle damage and subsequent inflammation. Cats, especially long-haired breeds, are more often infected than short-haired breeds. Some of them can become chronic carriers of the fungus even though they may not show any signs of infection.
If your cat has patchy or circular hair loss, scales (dandruff) and reddened skin you should bring your cat to FeederCreek. Your cat will only be itchy 50% of the time. Your vet at FeederCreek will most likely want to do a DTM test or a fungal culture to confirm the diagnosis. A Wood’s Lamp can be used but will only diagnose 50% of ringworm caused by Microsporum canis, the most common cause of ringworm.
Treatment of infected pets can be both expensive and frustrating, especially in households or kennels where several animals live.
After reviewing the most current published papers, I would like to summarize the most effective treatments. Although each treatment protocol most be tailored to your cat and environment. All cats in the household should be tested to determine if they are carriers even if they are not showing clinical symptoms.
The optimum treatment involves clipping your cat’s entire hair coat, twice weekly topical antifungal therapy, concurrent systemic antifungal therapy, and environmental decontamination. The best topical product is a Lime Sulfur dip, which should be done twice weekly. Lime Sulfur should not be rinsed off your cat. There are two commonly used oral systemic therapies. One is Itraconazole for 28 days, followed by pulse therapy of one week on and one week off for 4 weeks. The second is Terbinafine; it is the newest drug and should be used for 28 days. Finally, the environmental decontamination involves using a 1:10 bleach to water mixture twice weekly to disinfect brushes, beading, and bowls. This combined treatment should not stop until three negative consecutive fungal cultures are obtained at bi-weekly intervals.
Jonathan A. Yardley, DVM