I have a blue dog that is starting to develop bald spots. I need information on alopecia in blue dogs. I know that it's a loss of hair, but is it rare or common? What is color dilution alopecia?
Color dilution alopecia (CDA) is a genetic condition involving the hair follicles of some blue- or fawn-colored dogs and is characterized by eventual permanent loss of the blue- or fawn-colored portions of the affected dog's haircoat. Although the specific cause is not known, CDA is associated with genes that determine the haircoat's color. Some dogs inherit genes that code for "dilute" haircoat colors. The colors black or brown, when diluted, appear blue or fawn, respectively. Blue- or fawn-colored dogs apparently have a genetic tendency to develop alopecia, or baldness, although only some of these dogs actually develop CDA. Doberman pinschers with dilute haircoat color seem most likely to develop CDA. Other breeds that may frequently develop CDA include dachshunds, Great Danes, and Yorkshire terriers, among others.
The unusual dilute coloring is associated with abnormal pigment in the hairs. Clumped pigment within the hairs may weaken the hair shaft and lead to breakage of the hair. Hair follicle activity gradually diminishes and regrowth of the broken hairs eventually stops. A microscopic exam of the broken hairs will reveal the abnormal pigment-bearing packets and abnormal hair follicles as well.
Frequently the process begins with superficial bacterial infection of the hair follicles (folliculitis) and hair loss in lightly colored areas. Despite antibiotic treatment and resolution of the rash associated with the folliculitis, the hair tends not to permanently regrow. The rate of hair loss varies from case to case. In general, the more dilute the color the earlier the onset of hair loss. Most light colored dogs that have CDA will be hairless by two to three years of age.
Aggressive grooming, strong shampoos and other trauma to the hair can accelerate the hair loss, so these should be avoided. The process is likely to progress and no definitive treatment is known. Some veterinarians believe that retinoic acid derivatives are helpful. However, these preparations are not curative. Certain drugs may improve or limit infection-associated inflammation in the skin that hastens hair loss. Some clinicians have suggested a role for melatonin in the treatment of CDA also.
Problems other than CDA may cause alopecia; these disorders may be age-dependent. Young dogs with hair loss and superficial infection may have red mange (demodicosis) or other disorders of the hair follicles. In older dogs hypothyroidism and other endocrine diseases may cause hair loss. These problems should be ruled out before a diagnosis of CDA is made.
I encourage you to speak with a veterinary dermatologist about any new or investigational treatments for CDA. Your veterinarian may be able to refer you for a consultation or to arrange for you to speak directly with a veterinary dermatologist about your dog.
11/03/03
