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Q&A: Why Is My Dog Losing Hair on the Corners of Her Mouth?

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Dr. Mark is a veterinarian. He has been working with dogs for more than 40 years.

There are many potential causes for hair loss in dogs, but it's impossible to truly diagnose without trip to the vet.

There are many potential causes for hair loss in dogs, but it's impossible to truly diagnose without trip to the vet.

Why Is My Dog Losing Hair Around the Mouth?

"My 14-year-old beagle just started losing hair on the corners of her mouth. One side is worse than the other. What can this be from? She is on an oral tick-and-flea prevention medicine." —Kristen

Dr. Mark's Answer: Causes of Hair Loss in Dogs

There are a lot of causes for hair loss in dogs, but around the lips and mouth there are fewer possibilities. Here are the main ones:

  • demodectic mange (Demodex mites)
  • ringworm
  • food or contact allergy (1)
  • autoimmune disease (2)
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Take a Trip to the Vet

This is not something that can be diagnosed with only a description or even a good photograph. Any dog that losing hair around the mouth needs to be examined and may need to have his skin scraped to look for mites, cultured to find ringworm, or even biopsied to find changes consistent with an autoimmune disease or cancer.

Your dog may also need to be on a special diet and have his feed bowls changed if allergies are suspected.

Skin diseases are not usually emergencies, but it is a good idea to take care of them as soon as possible before they spread and cause permanent scarring.

Sources

  1. Olivry T, Prélaud P, Héripret D, Atlee BA. Allergic contact dermatitis in the dog. Principles and diagnosis. Vet Clin North Am Small Anim Pract. 1990 Nov;20(6):1443-56. https://pubmed.ncbi.nlm.nih.gov/2251735/
  2. Tham, H. L., Linder, K. E., & Olivry, T. (2019). Autoimmune diseases affecting skin melanocytes in dogs, cats and horses: vitiligo and the uveodermatological syndrome: a comprehensive review. BMC veterinary research, 15(1), 251. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6639964/

This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2022 Dr Mark

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