The most common treatment for a ringworm infection in dogs is a customized, medicinal shampoo. These shampoos typically contain agents, such as miconazole or lime sulfur, that are critical in killing the dangerous fungus. In some cases, vets also prescribe oral medications.
Veterinarians usually customize a treatment regimen for ringworm based on the severity of the infection, with the most severe cases calling for both oral and topical treatments. It is not uncommon for the vet to instruct the owner to shave or clip away the fur from the site of infection so that treatments are most effective. Lesions typically take about two to three weeks to clear up after the shampoo is first applied. The owner should also dispose of the infected animal's bedding, blankets and toys.
It is extremely important to treat ringworm lesions for the full time instructed by the vet, as the infection can persist even after visible lesions have disappeared. Consequently, the vet may want to run diagnostic tests to ensure that the animal is cured. Additionally, if the infected dog shares a home with other pets, the owner is likely directed to shampoo all the other animals with medicinal shampoo. Even without a host, the fungus can survive in the immediate environment for months. Constant vacuuming and hand-washing is also recommended, as this can prevent passing the disease to humans.