Posted on Jan.08, 2012, under Misc
Alopecia is the partial or complete lack of hairs in areas where they are normally present. Hair loss is a sign and its underlying cause must be determined for the condition to be successfully treated. If a dog has hair loss and is also scratching the area excessively, the itching should be investigated first.
There are many causes of hair loss, which can be congenital or acquired. Congenital means the animal is born with the condition. Congenital hair loss may or may not be hereditary. It may be apparent at or shortly after birth. In acquired hair loss, the dog is born with normal hair coat. It has or had normal follicle at one time, and is or was capable of producing structurally normal hairs. Any disease that can affect hair follicles can cause hair loss. Acquired hair loss can be inflammatory or noninflammatory.
Disease that can directly cause destruction or damage to the hair shaft or follicle include bacterial, fungal or parasitic infections, skin trauma such as burns, and poisoning caused by mercury, thallium, or iodine. These diseases tend to be inflammatory.
Diseases that can directly inhibit or slow hair follicle growth include nutritional deficiencies (particularly protein deficiencies), or hormonal imbalances such as hypothyroidism. Temporary hair loss can occur during pregnancy, lactation or several weeks after a severe illness or fever. These types of hair loss tend to be noninflammatory unless a secondary infection of the skin develops.
Itching or pain is a common cause of acquired inflammatory hair loss. Diseases that commonly cause itching or pain include infections, parasites, and allergies. Friction may cause local hair loss, for example poorly fitted halters or collars.
Signs of hair loss may be obvious or subtle, depending on the disease. Congenital or hereditary hair loss is commonly either symmetric or located in one area only. It is not usually accompanied by inflammation. Bilaterally symmetric hair loss, mainly occur in male dogs. More prevalent in certain breeds, including ChowChows, Keeshonds, Pomeranians, Miniature Poodles, Airedales, and Boxers.
Signs of acquired hair loss are varied and often influenced by the underlying causes. Inflammation, color change, scaling, excessive shedding, and itching are common. Some causes may lead to the development of the secondary skin diseases, such as infection or fluid discharge.
An accurate diagnosis of the cause of hair loss requires a detailed history and physical examination. Key points in the history include the breed’s tendency for congenital or hereditary hair loss, the presence, duration, and progression of problems, evidence of infection and general health problems.
The physical examination will cover both the dog’s skin and its general health. The hairs will be examined to determine if they are being shed from the hair follicle or broken off. Your veterinarian will also look for signs of secondary skin infections or parasites and may perform skin scrapings and comb the hair coat for fleas, mites and lice. Your vet may order diagnostic laboratory tests. These usually smears and culture of the skin to check for evidence of bacterial, fungal, or yeast infections. A skin biopsy may be performed to confirm bacterial and parasitic causes of hair loss or to identify cancerous causes of hair loss.
Successful treatment depends on the underlying cause and specific diagnosis. Identifying the underlying cause will take some time, and your veterinarian will prescribe medication to relieve any discomfort your pet has in connection with hair loss.