Ringworm is a fungal infection affecting the skin, hair, and nails and is also known as dermatophytosis. Ringworm affects many mammalian species including cattle, sheep, goats, swine, horses, dogs, and cats. It is also zoonotic, meaning that humans can get infected from animals as well. It is highly infectious among animals and between animals and humans, so be sure to wear gloves and wash hands when handling an animal with a known or suspected ringworm infection.
There are many species of fungus that cause dermatophytosis. Most of these species of ringworm do NOT glow under Wood’s Lamp, so it is not an effective means of diagnosis. Fungal culture is the only test that can definitively diagnose dermatophytosis, but results can take as long as three weeks. However, ringworm has distinctive lesions that can indicate an infection to you and your veterinarian.
Ringworm lesions are typically individual, circular areas of hair loss that may have scaling, crusting, and/or oozing along with redness or inflammation. Lesions are commonly found on the face, neck, chest, and limbs. These lesions may only become evident after shearing, so it is important to disinfect clippers between animals or use an entirely different set after clipping an infected animal.
While ringworm typically self-resolves, there are treatments that can aid the process and reduce spread since resolution may take 4 to 12 weeks. Supportive treatment of ringworm typically consists of topical therapy and adjustments in husbandry, as overcrowding can perpetuate infection among individuals. Isolation of infected animals until resolution of lesions is ideal when possible. Please consult your veterinarian for use of topical therapies. Resolution is usually determined by new wool or hair growth in the lesion and supported by hair or wool around the edge of lesion not being easily removed when pulled.
As a reminder – animals that have active ringworm lesions should NOT be taken to the fair, especially given the zoonotic and contagious nature of the disease.
To see how ringworm lesions may progress overtime, please see the infographic provided below.
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