The best treatment for feline ringworm depends on how severe the case is, but common options are medicated shampoos, ointments or oral medications, according to WebMD. Ringworm is actually a fungal infection, so treatments are geared at killing the existing fungi and preventing regrowth.
Fungal infections are notoriously difficult to treat, and feline ringworm infections may require ongoing treatments that can take several months or more. It is also important that any environmental factors contributing to the infection, such as dirty bedding or affected carpeted cat toys, are cleaned or removed to prevent reinfection.
Treatment with topical medications may require shaving the cat's hair to allow for easier access to affected areas and to ensure the ointments are able to be applied directly to the infection. Unless it is a very mild case, topical treatments are generally not enough to fully eradicate the infection and are more commonly used in combination with other treatments. Topical treatments, including medicated shampoos on a weekly basis, need to be continued for several weeks.
Oral medications can help treat feline ringworm from the inside, but these medications also need to be administered over several weeks, with 6 weeks being the minimum, according to VCA Animal Hospitals. There are several types of medication that can be used to treat ringworm, and the veterinarian decides which one by weighing the benefits against the different side effects. Fungal culture will be taken throughout the course of treatment to monitor progress.