Aaron C. Rainer, D.V.M., M.P.H.
East Lake Veterinary Clinic
Killeen, TX
Ringworm is a common skin condition with a deceiving name. Ringworm is not caused by a worm at all. Ringworm is a skin infection that commonly affects pets and humans. It is caused by a group of fungi called dermatophytes that consume dead skin and hair and can cause a classic “round” lesion on the body. However, exposure to the fungus, commonly found in hot & humid environments does not necessarily result in infection and infection may not result in any clinical signs. Nonetheless, ringworm is a significant dermatology issue. Once exposed to ringworm, it may take anywhere from one week to one month to manifest clinical signs.
Signs & Symptoms
Clinical signs may begin as a simple poor hair coat and may progress to patchy or circular hair loss. Signs could also include scaly, red, crusty, pigmented, and/or itchy skin.
How does my pet get ringworm?
The ringworm fungi have millions of spores that are in the environment. All it takes is for one of those spores to land on an animal, and they could develop ringworm. Ringworm is contracted through direct contact with a dermatophyte fungal spore. Although puppies and kittens are at greater risk of contracting the infection, adults are not immune.
Are Humans At Risk?
Yes. Ringworm is contagious from animals to humans as well as from the environment to humans. Ringworm is categorized as a zoonosis, which means that ringworm can be passed from animal to human. Although anyone can get ringworm, those that are generally considered to have susceptible immune systems such as elderly, children, chemotherapy patients, and HIV positive patients are at higher risk of getting ringworm.
Diagnosis
There are three methods your veterinarian may choose to diagnose ringworm. A Wood’s lamp evaluation is one method of identifying ringworm, but it is only accurate in about 50% of cases. A positive Wood’s lamp evaluation yields an apple green fluorescence. A veterinarian may choose to examine a hair sample under a microscope also. The best means of confirming a ringworm diagnosis, however, is by fungal culture or skin biopsy.
Treatment
Treatment of ringworm is time consuming. It requires patience and due diligence of the pet owner to treat both the patient and the environment. Ringworm can be both frustrating and expensive to treat, especially in multianimal households or recurrent cases. Your veterinarian may choose one or a combination of therapies to treat ringworm. You should consider confining or quarantining the pet since ringworm is contagious to humans and other animals. There are several drug choices that veterinarians may choose for the treatment of ringworm. Your veterinarian may also choose to supplement with a variety of dips and shampoos during the treatment. Typically, it takes about three weeks up to two months to treat ringworm. If treatment is stopped prior to a negative fungal culture, then ringworm could reoccur.
Environmental Clean-Up
Just as important as treating the patient is treating the environment. A diluted bleach solution (1:10) has been proven to remove most of the fungal spores in the environment. However, not everyone chooses to use a bleach solution on their carpet. Therefore, you may be able to do more by vacuuming numerous times or by using a steam cleaner to reduce environmental contamination.
If you are concerned and suspect ringworm, consult your local veterinarian.
