Pattern Baldness in Dogs

Dogs, like people, can be afflicted with a disorder known as pattern baldness, a symmetrical loss of hair with no known underlying disease. In some cases, hyperpigmentation of the skin materializes where the hair is lost, and the skin grows darker. The overall triggers for pattern baldness are believed to be genetic in nature, and certain breeds are more likely to develop this disorder than others. A few of the several breeds that are over-represented include Dachshund, Boxers, and Chihuahuas. Although unsightly, this disorder is primarily cosmetic in nature, and it doesn’t cause itching, swelling, or pain.

Pattern baldness, or the symmetrical loss of hair, is a genetic abnormality that causes unsightly bare patches, but rarely causes any discomfort to the animal.

Most forms of symmetrical baldness occur after the dog is six months old or older, although some types of non-symmetrical alopecia may occur when they are just puppies. The most common places to find baldness on dogs are around the temples, the front of the throat area, the flank, and the back of the thighs. The skin may or may not become hyperpigmented, and unless a secondary condition has developed, no pain or swelling is involved with this disorder. 

• Hair loss (temples, throat, flank, back of thigh)
• Hyperpigmentation of the skin (sometimes)

Types

• Alopecia X - Canine alopecia X, also known as Black Skin Disease, affects adolescent or adult who then dogs lose their hair in symmetrical patterns; the skin underneath the lost fur blackens due to hyperpigmentation 
• Seasonal (Recurrent) Flank Alopecia - Dogs with this disorder lose hair symmetrically in the flank area on a seasonal basis; the season that the flank is affected can differ from dog to dog, however, fall and spring are typical 
• Symmetrical Pattern Alopecia - A relatively common skin condition where the hair begins thinning as early as six months old, usually on the head, neck, chest and thighs; hyperpigmentation sometimes occurs, but not always

Pattern baldness is typically caused by a congenital form of follicular dysplasia, which is the gradual thinning of the hair due to a structural abnormality or narrowing of the hair follicles themselves. Although most forms of follicular dysplasia can cause alopecia, or balding, not all of them cause pattern balding. Some conditions, such as obesity, hormonal imbalances, and stress, may contribute to the development of alopecia.

Pattern baldness is a diagnosis of exclusion, so several testing methods are likely to be utilized. Skin samples are typically collected from any areas that are affected by the baldness, both for utilization in the microscopic examination of the skin cells known as a cutaneous cytology and for use in a biopsy, and hair samples including the roots may be evaluated by the laboratory as well. The results from the cutaneous cytology and the biopsy can help the examining veterinarian to eliminate other issues that can cause the loss of hair, such as bacterial or fungal infections or infestations by parasites such as mites or fleas. 

Typical blood tests like a biochemistry profile and complete blood count will also be employed to check for disorders such as a systemic infection or even hormonal imbalances which can cause similar symptoms. Some of the hormonal disorders that incorporate canine baldness as a symptom include hyperthyroidism and Cushing’s disease (hyperadrenocorticism).

Pattern baldness is not usually curable, although melatonin is a hormone supplement that may stimulate the regrowth of the fur. Although other forms such as a capsule, sublingual, and powder form are seen, this hormone is typically administered to canines by way of a tablet. A veterinary professional should always be consulted before adding supplements to your dog’s routine to ensure there will be no adverse effects due to pre-existing conditions or other medications. If treatment with melatonin is successful, signs of regrowth will occur after approximately six to eight weeks. 

In certain cases, particularly with Alopecia X, spaying or neutering the animal may result in the re-growth of the coat. Unfortunately, these situations are often temporary, and the hair loss returns. Skin affected by pattern baldness is slightly more prone to developing bacterial infections, and if the results from the diagnostic tests are indicating that a bacterial infection may be present, then either oral or topical antibiotics will be prescribed to eliminate the disease.

If your pet has had antibiotics prescribed to them, it is important to ensure that your pet continue with the medication for as long as is recommended by your veterinarian, sometimes even after symptoms have faded. This will help to prevent the recurrence of the bacterial infection. Dogs that have patches of skin that are bare will require regular bathing to remove dead skin cells, and the uncovered areas should also be moisturized regularly to maintain elasticity. The parts of the dog that are exposed to the sun will be more prone to sunburn and melanomas than furred areas, and any bare spots should be treated with sunblock to prevent complications.