Cyclic flank alopecia is a condition in which hair falls out, leaving defined bald patches on the body. There is no itchiness or other skin changes. It tends to occur more commonly in winter and affects the flanks (sides of the body). The hair often regrows after 3 to 8 months. Symptoms can start at any age, but the most common age range is between 3 and 6 years. Cyclic flank alopecia is also known as seasonal flank alopecia or canine flank alopecia.
Causes
The exact cause is unclear, but variations in light exposure duration seem to play a significant role.
Risk
Breeds that are more prone include Boxers, Airedale Terriers, English Bulldogs, Schnauzers, and French Bulldogs.
Symptoms
The main symptom is hair loss, leading to defined bald patches without any other lesions. It usually occurs on the flanks (sides of the body just in front of the back legs). The symptoms are usually symmetrical. The nose, armpits and tail base are sometimes also affected. Hyperpigmentation (darkening of the skin) of the bald areas may be seen too.
Diagnosis
It may be diagnosed by a physical examination, but often other conditions may need to be ruled out with the following tests:
Skin scrapes, hair plucks or tape strips
A skin biopsy
Blood and urine tests
Treatment
For many cases, no treatment is needed. Melatonin has been used successfully in some cases.
What to expect
For many dogs, the symptoms recur every year. Less commonly, in some dogs, the hair never grows back. Other dogs recover completely. The condition is purely cosmetic, and affected dogs are otherwise in good health.
Prevention
Unfortunately, there is no way to prevent this condition. To help keep your dog's coat in good condition, make sure they are eating a complete and balanced diet, prevent obesity and make sure they get regular vet-recommended parasite control.