Seasonal Flank Alopecia: Why does my dog get bald spots in the winter?

What is Seasonal Flank Alopecia? It is a condition of certain breeds of dogs in which their hair falls out in the late fall or spring or both. It is seen most commonly in areas of the country with dark winters such as the Midwest. The condition is not well understood, but is thought to be from lack of sunlight exposure to the pineal gland. The pineal gland is located at the base of the brain and is the gland responsible for telling bears to hibernate and telling us to crawl into bed early during these long winters. The pineal gland controls release of the hormone melatonin. When an animal has less exposure to sunlight, melatonin production, as well as other hormone levels decrease.
What does it look like? Typically, the dog will develop symmetrical bald patches on the sides of the chest or lower back area. The skin usually looks darker in the bald patches. This condition is not itchy, but the bald patches are more prone to getting bacterial skin infections.
Which breeds are most commonly affected?
· Airedales
· English Bulldogs
· Boxers
Other breeds this can affect:
· Miniature schnauzers
· Miniature poodles
· Doberman Pinschers
· Bouvier d Flanders
· Scottish Terriers
· French Bulldogs
· Labrador retrievers
What is the treatment? The hair usually grows back on its own in 3-4 months, so no treatment is necessary. When the hair grows back, it may grow back as normal hair, or it may grow back as a different color or texture. The condition may not return every year, but for the dogs that it happens to frequently, permanent baldness may result. Giving melatonin supplements may also help resolve the condition, but response to treatment is variable.
Be Careful: This condition can be confused with other skin diseases like hypothyroidism, Cushing’s disease, estrogen or testosterone imbalances, post-clipping alopecia, skin infections, or alopecia X, so it’s important to have your dog examined by a veterinarian.

Submitted by Teresa Hershey DVM