The word "alopecia" means loss of hair. The skin and hair is considered a "mirror", or outward expression, of the general health of the body. Loss of hair is usually a symptom of another disorder. Hair follicles, skin, and the lining of the gastrointestinal tract are active tissues with a high rate of regeneration and replacement. These are the tissues which are first affected when some sort of toxic substance is ingested. For instance, when receiving chemotherapy for cancer, the side effects include GI upset such as nausea and vomiting, and disturbance of the hair follicles, causing a (usually temporary) alopecia. Alopecia is a common symptom for many conditions, and can indicate an uspet in the natural chemical balance in the body. Poor circulation can also result in alopecia.
Other causes of alopecia can include hormonal imbalances, allergies, immune deficiency, stress, parasites, infections (yeast, fungal and/or bacterial) and nutritional deficiencies.
Many of our Pomeranians have been affected by a condition known as "Alopecia X". This condition is a type of non-inflammatory alopecia. It is also known as black skin disease or coat funk. "Non-inflammatory" means that the skin is not itchy, inflamed or irritated. The diagnosis of Alopecia X is made when all other causes of hairloss have been ruled out. Characteristically, the hair thins on the thighs and trunk, progressing to baldness in those areas. The head and distal extremities are spared. The longer guard hair is usually lost first, which leaves the fuzzy puppy-type undercoat which is eventually lost also. The skin eventually darkens. It is not inflamed or itchy, and does not normally get infected. Hair regrowth following clipping is slow or absent. The age of onset of this condition is variable, ranging from adolescence to adulthood. The condition has been noted to be familial in occurrence. Dogs have been noted to be affected more frequently than bitches. Spitz or nordic breeds are most commonly affected. This disorder has become a significant concern for our breed because of its widespread occurrence. Complicating the picture is the fact that many differing treatment options can be effective, leading us to believe that we are dealing with not one single condition, but possibly many different, separate problems.
The fact that we usually see more males than females with Alopecia X could mean that this is a sex-linked disorder. However, because the results with breeding have not proven predictable in this manner, it could be that this disorder is polygenic...requiring two or more genetic factors to occur....or the disorder could be sex-influenced. In other words, the inherited tendency toward development of coat loss may be there, but unless a certain trigger occurs (such as a certain hormonal influence), then the dog will not go on to develop symptoms of coat loss. Note that in these situations, the dog would still carry genetic factors for coat loss to pass on to following generations, even though he himself may not display any symptoms.
Many endocrine (hormonal) disorders produce symptoms of coat loss similar to Alopecia X. These include thyroid disorders, adrenal gland problems, growth hormone deficiency, and sex hormone imbalances. Neutering of affected dogs and bitches will sometimes cause hair regrowth, supporting this last theory.
If your dog starts to develop a hair loss problem, your vet will likely first check for parasites, allergies and other common conditions. He may then decide to check thyroid hormone and cortisol levels. Skin biopsies are considered if thyroid and adrenal hormone levels are normal. A biopsy may determine if the alopecia is not hormone-related, but instead related to abnormality of the hair follicles such as sebaceous adenitis or color-dilution alopecia. Skin biopsies in cases of Alopecia X may show a miniaturization of hair follicles, with the skin normal to decreased thickness. A skin biopsy is suggestive, but not confirmatory, of Alopecia X.
The thyroid gland controls metabolism through the entire body, and deficiency is often manifested first by loss of hair and cold intolerance. Upon diagnosis by a blood thyroid panel, oral thyroid hormone replacement will be necessary for life. Proper balance of thyroid hormone is necessary because too much circulating thyroid hormone is just as bad as too little....high levels of thyroid hormones can cause rapid heart rate as well as...alopecia.
Alopecia is also a symptom of Cushing's disease, a problem in which the adrenal glands produce excessive cortisone-type hormones. Cushing's disease is also characterized by hunger, thirst, and a pot-bellied appearance. Cushing's disease can be due to overactivity of the adrenal gland itself, or the pituitary gland which stimulates the adrenal gland. Cushing's disease can also be the result of administration of cortisone-type hormones for other conditions such as allergies, arthritis or asthma. These cortisone-type hormones include vetalog, azium, prednisone, prednisolone, dexamethasone, depo-medrol and others.
Treatment of Cushing's disease with Lysodren (mitotane) is sometimes attempted by veterinarians. This drug erodes the adrenal cortex. It can also affect the sex hormones which are produced by the adrenal glands. Lysodren is sometimes used to treat adrenal sex-hormone alopecia. In one study, 12 of 12 chows were noted to respond. In another study, 4 of 6 dogs were noted to respond. However, if the adrenal glands are damaged too much by the Lysodren, an adrenal steroid deficiency known as Addison's disease can result, so Lysodren treatment needs careful monitoring by a veterinarian. A symptom of Addison's disease? You guessed it....loss of hair!
Trilostane is a drug which is used to treat Cushing's disease. It interferes with the adrenal gland production of steroids. In an Alopecia X study done in 2004, positive response was noted in 13 of 16 Pomeranians, and 8 of 8 miniature poodles. Trilostane is well tolerated, but is expensive and must be ordered from abroad at present.
Growth hormone is secreted by the pituitary gland and is necessary for hair growth and the maintenance of normal elasticity of the skin. Dogs affected by growth hormone deficiency have varying degrees of hair loss and darkening of the skin, but are otherwise healthy. Assessment of growth hormone or serum insulin-like growth factor (IGF) in response to a growth hormone stimulant can be done for diagnosis. Growth hormone administration has been tried for alopecia X. This type of treatment is very costly. In addition to alopecia, growth hormone deficiency is associated with a form of dwarfism known as "pituitary dwarfism". Growth hormone levels affect blood sugar... excess growth hormone can result in diabetes, while growth hormone deficiency can cause hypoglycemia, dwarfism and alopecia.
Cyclic flank alopecia is related to endocrine disorders, and may relate to light cycles, because hair loss and regrowth tend to be seasonal. (Some affected breeds are the Airedale terrier, Affenpinscher, Bearded Collie, English bulldog, Boxer, Scottish terrier). Treatment with the pineal hormone melatonin is sometimes attempted.
Melatonin is secreted by the pineal gland, a pea-size structure at the center of the brain. As our eyes register the fall of darkness, melatonin production begins. At night, melatonin is produced to help our bodies regulate our sleep-wake cycles. The amount of melatonin produced by the body seems to lessen with age. Scientists believe this may be why young people have less problem sleeping than older people. Melatonin is also believed to act as an antioxidant. It reduces free radical damage, stimulates an aging immune system, protects the cardiovascular system, preserves a youthful circadian rhythm; and stimulates the production of growth hormone. Oral melatonin supplementation has been found to be effective for hair regrowth in 50-75% of these cases of cyclic flank alopecia. It should be administered in the evening, due to the natural sedating effects.
Melatonin interacts with another hormone produced by the pituitary gland, prolactin, which regulates seasonal shedding and stimulates lactation in the bitch. Elevated prolactin levels result in the heavy shedding in bitches who have recently whelped a litter. Interestingly, prolactin is closely related to growth hormone.
Diagnosis of Alopecia X may be based on response to therapies. Neutering is recommended initially. If neutering is ineffective, oral melatonin supplementation may be tried for a three month period. Melatonin is noted to produce partial to complete coat regrowth in 50-60% of cases. Should melatonin therapy fail, methyltestosterone administration may be attempted. However, this can cause liver problems and aggressive behavior. Should melatonin or methyltestosterone fail to be of benefit, sex hormones are measured by blood tests. If adrenal sex hormone levels are abnormally high, treatment may be attempted with mitotane (Lysodren) or trilostane.
There are some other drugs which have an effect on the adrenal hormones. These have been used for Alopecia X treatment, with varying results. The drugs include Prednisone, anipryl, ketoconazole, leuprolide and cimetidine.
There is data to suggest that Alopecia X may be a primary hair growth disorder: a genetic predisposition to the development of a defect in the hair growth cycle, rather than a hormonal condition. There is also a theory that certain hormones may adversely affect the hair follicles in genetically susceptible dogs.
There are ongoing research studies on the possible heritability of Alopecia X. Liz Hansen at the University of Missouri is involved with one such study. She is happy to report that due to recent advances in technology for mapping canine DNA, some painstaking advances are being made in research. Liz is sending out a plea for more participation in this study. She especially needs blood from the normal, nonaffected close relatives of dogs affected with alopecia X. A close relative would be considered a sibling (littermate or same breeding) or a parent of an affected dog. By examining the chromosomes that differ between the relatives, they may be able to further isolate an area which could be responsible for an inherited alopecia. For more information on the study, see:
or contact Liz: email: HansenL@missouri.edu
by phone, 573-884-3712
Once Alopecia X is considered as the most likely diagnosis, no further workup may be necessary if the owners are willing to live with an alopecic pet. Risks of therapy must be weighed against the benefit of enhanced appearance.
OTHER CANINE GENETIC COATLOSS CONDITIONS
There are some other genetic conditions associated with alopecia, including seborrhea, dermatomyositis, and sebaceous adenitis.
"Follicular dysplasia" is a term for a genetic non-inflammatory alopecia in many breeds. Black hair follicular dysplasia is a hereditary alopecia in dogs with some black fur. A genetic defect in melanin transfer and hair shaft formation is thought to be involved. This is inherited as an autosomal recessive trait, and has been noted in the American Cocker Spaniel, basset hound, beagle, border collie, dachshund, Gordon setter, Parson Russell terrier, papillon, pointer, saluki and schipperke, as well as mongrels. Hair loss occurs in the areas of black patches of skin.
Wooly syndrome is common in Siberian huskies, and occasionally affects Alaskan malamutes and English springer spaniels. Primary hairs are lost and the undercoat is crimped and dry, like wool. Alopecia may occur in pressure areas.
Saddle alopecia is seen in Airedale terriers and Portuguese water dogs. Hair loss occur on the dorsum in a saddle-like pattern.
Greyhound alopecia is more prevalent in working dogs, and stress is felt to be a prominent causative factor.
Color dilution alopecia can occur in dogs bred for unusual hair color. The dilute form of black to blue and red to fawn cause by "dd" dilution is associated with this disorder. Not all "dd" homozygous recessive dilute dogs develop alopecia. There is considerable breed variability. Blue and fawn Doberman pinschers are commonly affected. The main breeds affected are the Bernese mountain dog, Chihuahua, chow chow, dachshund, Doberman pinscher, great Dane, Irish setter, Italian greyhound, minature pinscher, saluki, schipperke, Shetland sheepdog, standard poodle, whippet, Yorkshire terrier and rottweiler. Note that only the "dd" color dilute specimens in these breeds are affected.
Coat dilution alopecia is seen in Irish water spaniels, Portuguese water dogs, and curly-coated retrievers. Hair loss is attributed to fracture of the hair shafts.
Spiculosis refers to a hair follicle defect in which hairs are brittle and thickened and form nodules known as spicules. In all likelihood, the defect originates from abnormal fusion of primary and secondary hairshfts, whth an onset between 6 and 12 months of age. The mode of inheritance is unknown, but the condition primarily occurs in male Kerry blue terriers.
X-linked ectodermal dysplasia is a rare condition seen in German shepherd dogs characterized by symmetrical areas of hairlessness, together with missing or misshapen teeth.
Alopecia areata is a rare autoimmune disease characterized by non-inflammatory focal alopecia. The production of autoantibodies against the hair follicle results in loss of hair, most commonly on the head and neck, but may occur anywhere on the body.
Vitamin A responsive dermatosis is seen in the American cocker spaniel, Cairn terrier, and Labrador retriever. Zinc-responsive dermatosis occurs in Alaskan malamutes, American Eskimo dogs, Samoyeds, and Siberian huskies, as well as Doberman pinschers and Great Danes. These conditions are not the result of a dietary deficiency, but of a genetic predisposition to poor absorption of either Vitamin A or zinc, respectively. Massive doses of vitamin A and zinc may demonstrate improvement in the affected dog.
As is true with many characteristics, these alopecic conditions are often hereditary. This possibility should be considered when formulating breeding plans.
Many thanks to Geneva for allowing me to use this