by Barry B. Burtis D.V.M.
If your pet is completely or partially missing hair in areas where it is normally present, it has alopecia. Alopecia sometimes remains in relatively small localized areas, sometimes these small localized areas are found in multiple sites and occasionally it may be generalized, affecting most of the body.
Alopecia is not a disease, rather it's a problem, like a fever, that may be caused by a number of specific causes. In previous columns there has been discussion about how alopecia may develop and some of the things a veterinarian needs to do to try to identify some of the more common causes of the disorder. In this column I want to mention a few more causes for alopecia.
Colour dilution alopecia is characterized by hair breakage and loss in colour-diluted breeds. Many dogs have a hair coat colour that is said to be diluted. The colours are of a lighter shade, silvery gray (blue) instead of black or a sandy colour instead of red or brown. This disorder is genetic and inherited and although not common, is most likely to affect breeds with blue colour dilution. It may be found in Doberman pinschers, dachshunds, German Shepherds, great Danes, Italian greyhounds, whippets and Yorkshire terriers. There are a large number of other breeds that can be affected. The disease is primarily cosmetic but affected individuals are more susceptible to inflammation and infection of the skin. Owners with dogs who have colour dilution alopecia will need to avoid harsh shampoos and aggressive grooming practices that may cause increased breakage of hairs. It will also be necessary to provide good UV protection since affected skin will have increased exposure.
Recurrent seasonal flank alopecia is a skin condition that affects boxers, bulldogs and Airedale terriers and schnauzers, as well as certain other breeds. The exact cause is unknown. Hair thinning and baldness develops over the flank areas of an affected dog. In the northern hemisphere the onset is usually noticed between November and March. Most dogs will spontaneously regrow hair 3-8 months later. Episodes of hair loss may occur sporadically only once or twice or regularly each year. With repeated episodes there is often a progressive increase in the amount and duration of hair loss. Fortunately, this disorder also is a cosmetic disease that does not affect the dog's quality of life.
Alopecia X is a progressive loss of hair of unknown cause that develops most commonly in 2-5 year old plush-coated type dogs (Pomeranians, chow chows, keeshonds, Samoyeds) and in miniature poodles. It will be necessary to eliminate as a cause a number of hormone disorders that may closely resemble the nature and pattern of hair loss with this problem. Once confirmed to be alopecia X, a purely cosmetic ailment, benign neglect without any treatment becomes an option.
Cats are likely less frequently affected with alopecia disorders than dogs, however they can occur. Pinnal alopecia in cats is characterized by periodic episodes of hair loss from the ears. The ears do not seem to be itchy in affected cats and the hair loss may be patchy or involve most of the ear. Both ears are usually affected. Siamese cats seem to be predisposed to the condition. Peri-auricular alopecia is common and a normal finding in most cats. There is an area of sparsely haired skin on the head between the ears and eyes. It is more noticeable in some cats than in others.
Feline psychogenic alopecia is considered an anxiety neurosis. An affected cat licks and chews at the haircoat and causes a self-induced hair loss. It is important to rule out any other cause of hair loss and then try to identify and eliminate boredom or stress issues that be causing the abnormal behaviour. Barry Burtis is a local companion animal veterinarian. Past Pet Tales can be found at www.baycitiesanimalhospital.ca