Dermatophytosis, otherwise known as “ringworm,” is a fairly common fungal infection that can affect dogs, cats, and other animals.
“The term ‘ringworm’ actually comes from the circular, ring-like lesion formed on the skin of infected people; however, the disease itself is not caused by a worm at all,” said Dr. Alison Diesel, clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences.
Dermatophytosis is a zoonotic disease, meaning it not only can be transmitted to other animals, but to people as well. An animal or person can become infected with dermatophytes from contact with another infected animal, transfer from infected materials such as bedding and grooming equipment, or from the soil.
“Very young animals and older animals with other underlying illness are at higher risk for dermatophytes,” said Dr. Diesel. “Additionally, certain breeds of animals, such as Persian and Himalayan cats, and Jack Russell and Yorkshire terriers, have a higher tendency towards disease development.”
Dermatophytosis is the most common cause of alopecia, or hairloss, in cats. In addition to poor hair coat, it can also cause reddened skin, hyperpigmentation, and lesions.
“Lesions will often involve little red bumps called papules, scabs, and circular areas of hairloss. Anywhere on the body may be affected by hairloss, but face and paws will often have lesions,” said Dr. Diesel.
Because of this infection’s ability to spread all over the animal’s body and infect others, you should be sure to see your veterinarian for a proper diagnosis. A common way for veterinarians to diagnosis dermatophytosis is with a Wood’s lamp exam. This involves passing a fluorescent light source, or Wood’s lamp, over the animal and looking for glowing hair shafts. However, only a few strains of dermatophytes may glow, so this is not always considered to be the best approach.
“A better option for diagnosis is to perform a culture for the organism,” said Dr. Diesel. “Infected hairs or material may be collected by plucking hairs or brushing the animal with a new toothbrush and then submitting these hairs to a laboratory for fungal culture/isolation.”
Although your pet may be able to self-cure the disease on their own, therapy is typically recommended to minimize the amount of infective material present and thereby minimize spread of disease to others. “Treatment may involve strictly topical therapy with antifungal agents (such as lime sulfur) or may also involve oral antifungal medication as well,” said Dr. Diesel.
Treatment of exposed animals and other animals in the household should be considered in order to prevent the spread of infection. If you are concerned that your pet may have dermatophytosis, particularly if skin disease is noted in people in the household, you should contact your veterinarian immediately.
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