Ringworm in Dogs

Ringworm; it sounds like a parasite, but it’s not. Ringworm is actually a fungus—a particularly yucky fungus because some types are zoonotic, meaning it can be passed from one species to another. It can also be contracted from contaminated objects or soil. Ringworm has no favorites and likes all types of dogs, especially young dogs, those that are sick and have a suppressed immune system, as well as those living in high-stress situations, such as crowded and/or dirty kennels.

In most cases, signs of ringworm are fairly straightforward. Usually, ringworm starts with small, hairless lesions that look scaly. These may grow in size and tend to affect three areas of the body: the scalp, trunk, and nails. In some cases, pustules (pimple-like lesions) form on the surface of the sore. Your dog may or may not be itchy.

If your veterinarian suspects that your pooch has ringworm, diagnostic tests likely to be recommended include:

  • A fungal culture of the scales and hair from the lesion (The culture contains a special compound that, over time, helps indicate if the cause of the lesions is ringworm.)
  • Microscopic evaluation of hair from affected areas
  • NOTE: The fungal culture and microscopic evaluation are usually done in tandem.
  • Polymerase-chain reaction (PCR) testing of material from the lesions to detect ringworm DNA which can provide more rapid results than fungal culture.
  • If your dog is itchy, other tests including skin scrapings looking for mites and a blood test for scabies might be recommended.
  • Diagnostic tests, such as a biochemical profile, CBC, urinalysis, and a thyroid function to evaluate your dog’s overall health status

Depending of the seriousness of your dog’s infection, your veterinarian may recommend a topical or oral antifungal treatment, though often both are indicated. Treatment is monitored with repeat fungal cultures or PCR tests. Multiple negative tests are needed to prove the infection has been eliminated. It is very important to make sure that your dog’s bedding and your home are thoroughly cleaned, as the spores that cause ringworm can survive for a long time in the environment. Following your veterinarian’s treatment recommendations is very important to ensure a successful outcome and to prevent recurrence of this issue.

While ringworm isn’t common, it is very easily spread. Make sure your dog isn’t exposed to other pets with ringworm, and contact your veterinarian immediately if you suspect your dog has a lesion.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.


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Reviewed on: 
Tuesday, May 20, 2014