"Dysplasia" simply means an abnormality of development, such as an abnormality in the size, shape or organization of cells, tissues or organs. The term "follicle" refers to a sac or pouch-like depression or cavity. In this particular disorder, canine follicular dysplasia, the follicle involved is a hair follicle, which is the depression or invagination in the skin that contains the hair root and from which the hair grows.
Follicular dysplasia is a non-inflammatory disorder of a dog's haircoat. It results in hair loss and an abnormally poor coat quality. Sometimes, the pattern of hair loss is symmetrical; this is called pattern alopecia. "Alopecia" means hair loss. Other times, the hair loss is not symmetrical. Other names for disorders that are classified under this general condition are canine recurrent flank alopecia, cyclic flank alopecia, alopecia X, color dilution alopecia, blue Doberman syndrome and black hair follicular dysplasia. While each of these is a separate condition, they still all fall under the general umbrella category of canine follicular dysplasia.
Causes of Canine Follicular Dysplasia
There is evidence that canine follicular dysplasia – including symmetrical pattern alopecia (symmetrical hair loss), black hair follicular dysplasia, canine recurrent flank alopecia, alopecia X, and color dilution alopecia, among others - has a significant hereditary component, especially in certain breeds. Canine follicular dysplasia is a term that encompasses a number of hair-loss-related disorders. Color dilution alopecia (CDA) is genetically seen in certain breeds with dilute coat colors, such as blue Great Danes, Yorkshire Terriers, Dachshunds, Italian Greyhounds, Greyhounds, Whippets, Chihuahuas and Doberman Pinschers. Recently, so-called "silver Labrador Retrievers" have been diagnosed with color dilution alopecia, as have German Shepherd Dogs. Genetics are also attributed to black hair follicular dysplasia (BHFD), which is seen in some multi-colored breeds, such as the Bassett Hound and Saluki, and also in some solid colored dogs which are primarily black. Pattern alopecia also has a genetic component and is seen primarily in short-haired dogs such as Chihuahuas, Miniature Pinschers, Greyhounds, Whippets, Boston Terriers, Boxers and Dachshunds. Basically, it appears that all forms of follicular dysplasia and/or pattern baldness in domestic dogs are probably genetic in origin. There is no other reported cause for this disorder in dogs.
Prevention of Canine Follicular Dysplasia
Because this disorder is largely genetic in origin, there is no realistic way to prevent it, other than removing affected animals from the breeding pool.
The effects of canine follicular dysplasia usually do not bother affected dogs. This is largely a cosmetic condition rather than a medical one, unless secondary infections or sunburn occur as a result of the hair loss.
How Canine Follicular Dysplasia Affects Dogs
Dogs with follicular dysplasia typically do not suffer any adverse effects from their condition. The only time that they may be itchy or distressed is if their hair loss is significant and they develop secondary infections, sunburn or other irritation of their skin.
Symptoms of Canine Follicular Dysplasia
There are two general forms of canine follicular dysplasia: that which affects the ventrum of the dog (its belly area) and that which affects its ears (pinnae). In most cases, dogs are born with a completely normal haircoat and then, over time after about one year of age, have a gradual and progressive thinning or loss of their hair. Lightly colored dogs with color dilution alopecia (CDA) tend to develop hair loss by around 6 months of age, but it may not appear until 2 or 3 years of age in dogs that are darker, such as steel blue Dobermans. These dogs are prone to developing plugged hair follicles and recurrent secondary bacterial infections that can exacerbate the hair loss associated with the disorder.
Dogs with black hair follicular dysplasia (BHFD) typically have progressive hair loss and skin scaling, almost exclusively in areas of black skin. This can be seen as early as 4 weeks of age. Pattern alopecia on the ventral part of the dog's body (the belly area) is typically progressive starting at around 6 months of age. This syndrome is most commonly described in the Papillon and the Bearded Collie.
Dogs affected by cyclic flank alopecia usually develop symptoms between 1 and 5 years of age. As the name of the condition implies, they develop hair loss on their flanks and on the sides of their trunk; this hair loss is usually symmetrical. The skin in areas that are affected by this hair loss is often hyperpigmented, which means that it becomes darker than normal. Dogs with cyclic flank alopecia usually develop signs seasonally during periods of decreasing day length. Hair loss in these dogs tends to appear during the winter to spring months. Seasonal flank alopecia is seen in Boxers and Airedale Terriers, among other breeds.
Dogs at Increased Risk
Irish Water Spaniels, Red, Blue and Black Doberman Pinschers, Chesapeake Bay Retrievers, Portuguese Water Dogs and other breeds are predisposed to developing follicular dysplasia. The condition can develop in dogs of either gender, whether or not they are spayed or neutered. Non-color linked follicular dysplasia usually develops during adulthood. Color-linked follicular dysplasia, such as color dilution alopecia, black hair follicular dysplasia and pattern baldness, usually are apparent before one year of age. Color dilution follicular dysplasia is typically seen in dogs with diluted haircoat colors, such as blue Dobermans, Yorkshire Terriers and fawn Irish Setters, among others. Cyclic flank alopecia is seen in Airedale Terriers, Boxers and English Bulldogs, among many other breeds.
How Canine Follicular Dysplasia is Diagnosed
The diagnosis of follicular dysplasia is made primarily based upon the breed, the dog's history and the veterinarian's physical examination of the animal. External parasite infestation, such as that caused by the mites that cause demodectic mange, among others, must be ruled out as a cause of hair loss. Hypothyroidism and hyperadrenocorticism (Cushing's Disease), as well as other endocrine disorders, must also be ruled out as a cause of a dog's hair loss. Of course, the veterinarian will take a thorough history from the dog's owner and will conduct a thorough physical examination. Routine blood work and a urinalysis will typically be normal in a dog that is only affected by follicular dysplasia. Samples of the dog's hair and its roots down into the hair follicles will probably be taken and submitted to a laboratory for a diagnosis, which is called a dermatohistopathologic evaluation. A biopsy of affected areas is often helpful as well. This involves taking an actual sample of the skin from an area of hair loss and submitting it to a laboratory for examination by a pathologist, to determine the cause of the alopecia.
There are a number of different types of follicular dysplasia – or hair loss – in dogs. The exact cause of the hair loss may never be precisely diagnosed.
Treatment of Canine Follicular Dysplasia
The treatment for canine follicular dysplasia, in whatever form it presents, is largely supportive and involves medical management rather than a "cure". The goals of treatment are to restore hair growth if possible and to prevent secondary bacterial infections in or around the hair follicles. Some reports suggest that administration of melatonin may stimulate hair regrowth and/or shorten the duration of hair loss, although most of these reports are anecdotal and not supported by definitive scientific studies. Of course, if secondary bacterial skin infections are present, appropriate antibiotics should be prescribed and administered for the full duration of the prescribed course.
Other supportive therapies involve administration of frequent and appropriate topical medications or solutions. Oatmeal shampoos and other shampoos designed to sooth the skin can help to alleviate the dog's discomfort from this disorder. Skin moisturizers can also be beneficial. The dog's attending veterinarian can recommend appropriate shampoos, conditioners and moisturizers based upon the dog's particular condition.
The various types of canine follicular dysplasia are considered to be genetic. As a result, they are considered to be largely incurable. Fortunately, most affected dogs are otherwise healthy, suffering only from their hair loss and possibly from some associated bacterial skin disorders or an occasional sunburn. This is not a life-threatening disorder. Actually, it is largely a cosmetic condition and is much more of a distraction to owners than it is a real problem for the affected dog.