Black Skin Disease (Alopecia X) in Dogs: An Overview

Dog Breeds

“Black skin disease” is not actually a disease, but rather is a phrase used to refer to a form of hormonally-influenced, non-inflammatory, progressive, symmetrical hair loss and skin hyperpigmentation in dogs. The term for this condition preferred by breeders and veterinarians – especially veterinary dermatologists - is “Alopecia X.”

Read More >

Definition of Black Skin Disease

“Black skin disease” is not actually a disease, but rather is a phrase used to refer to a form of hormonally-influenced, non-inflammatory, progressive, symmetrical hair loss and skin hyperpigmentation in dogs. The term for this condition preferred by breeders and veterinarians – especially veterinary dermatologists - is “Alopecia X.” Alopecia simply means hair loss in areas where it normally is present. A number of other names are used as well, including adrenal sex hormone imbalance, growth hormone responsive alopecia, adult-onset growth hormone deficiency, coat funk, congenital adrenal hyperplasia-like-syndrome, wooly coat syndrome, follicular dysplasia and pseudo-Cushing’s disease. Another term is “hair cycle arrest.” Alopecia X is a form of patterned baldness, which means that affected dogs lose hair symmetrically on both sides of their body. Typically, hair loss is followed by darkening of the balding skin.

Causes of Black Skin Disease in Dogs

Little is known about this condition or its cause. Factors such as obesity, hormonal imbalances, allergies and genetics have all been suggested as contributors. One theory is that affected dogs have a genetic predisposition to some sort of hormonal imbalance, which somehow affects the function of cells at the level of the hair follicle. Another hypothesis is that there is some inherited defect in the normal hair growth cycle. It may be that Alopecia X is not a single disease at all but rather a combination of several, making diagnosis and treatment that much more difficult.

Preventing Black Skin Disease

Preventing Alopecia X is not realistic at this time, because the cause of the condition is so poorly understood. Certainly, weight management can remove obesity as a contributing factor. Because stress seems to exacerbate the signs of Alopecia X, owners should do their best to remove stressors from their dogs’ environment. Castration or spaying, dietary management and other hormonal or environmental management protocols may help to relieve the effects of stress and thereby reduce the hair loss and pigmentation changes associated with this disorder.

Special Notes

Alopecia X does not appear to affect a dog’s health. It seems to be a purely cosmetic issue for owners of affected animals, and benign neglect is often the recommended “treatment” of choice. Other conditions can be confused with Alopecia X. Currently, there are no medical tests to definitively diagnose this disorder. A veterinarian must rule out a number of other problems, particularly hypothyroidism and hyperadrenocorticism (Cushing’s disease), before concluding that Alopecia X is the cause of symmetrical baldness. This is called making a diagnosis by exclusion.

Symptoms and Types