Congenital hypotrichosis

What is ... ?: 

Dogs with this condition have hair loss at birth or by a few months of age, due to faulty development or a complete absence of some or all of the hair follicles from which the hairs normally grow. In some dogs other structures such as the sweat glands or the teeth are affected as well. The hair loss is not linked to coat colour as with colour dilution alopecia.
See also ectodermal defect.

How is ... inherited?: 

The mode of inheritance has not been established and probably varies, as does the condition itself, between breeds. Most cases have been seen in male dogs, suggesting a sex-linked inheritance. Some breeds have been intentionally bred to produce hairlessness, including the Mexican hairless dog and the Chinese crested dog.

What does ... mean to your dog & you?: 

The hairless (or alopecic) areas are commonly the head, ears and abdomen. Where hair loss is more general, there is usually only minimal hair remaining on the very top of the head, and at the end of the tail and legs. This is similar to the pattern of hair growth in dogs that are bred to be hairless.
This condition does not affect your dog's general health. Over time, the skin often becomes darkened and seborrheic (greasy, scaly and malodorous). Dogs with pale skin will be more susceptible to environmental damage, particularly frostbite or sunburn.

How is ... diagnosed?: 

Congenital hypotrichosis is suspected when a dog has areas of hair loss (that do not worsen) from birth or shortly thereafter. The diagnosis is confirmed through a skin biopsy, a simple procedure done with local anesthetic in which your veterinarian removes a small sample of your dog's skin for examination by a veterinary pathologist. The biopsy will show the absence or severe underdevelopment of hair follicles characteristic of this condition.

How is ... treated?: 

The hair loss is permanent. If seborrhea develops it can be managed with anti-seborrheic shampoos.

Breeding advice: 

Do not breed affected dogs or their parents. Where the condition appears to be sex-linked (occurring only in males), the mothers are carriers of the trait and should not  be used for breeding. 
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources: 

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Muller and Kirk's Small Animal Dermatology. p. 771.  W.B. Saunders Co., Toronto.


What breeds are affected by ... ?
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