Chronic Skin Disease: Sebaceous Adenitis
by Jenny Drastura
The disease occurs in Maltese, Lhasa Apsos, and probably Shih Tzu and Shelties, although no one knows the extent. I suspect that, like in Lhasas, it is highly underdiagnosed - assumed to be allergies, low thyroid, staph, etc. The treatment is quite different (and usually successful.)
Sebaceous Adenitis is a hereditary skin disease that occurs primarily in Standard Poodles and Akitas, but has also been reported in a number of other breeds, including the Maltese. (Other breeds include Collie, Dalmatian, Dachshund, German Shepherd, Golden Retriever, Irish Setter, Lhasa Apso, Miniature Pinscher, Old English Sheepdog, Toy and Miniature Poodle, Samoyed, Springer Spaniel, St. Bernard, Vizsla and Weimaraner.
The disease has been known since at least the 1960s, and carriers have been traced back to dogs in the 1950s.
SA can show up at any age. Signs include excessive dandruff, greasy or dry scaling, darkened skin, a musty odor, thickening of the skin and hair loss ranging from scattered to total baldness. These signs are caused by an inflammation of the sebaceous (oil) glands in the skin. As the disease progresses, the sebaceous glands and hair follicles are destroyed, leading to loss of hair. As part of the inflammatory process, secondary skin infections can occur.
There is no cure for SA, but it can be treated. Frequent baths and oil treatments have been found helpful in removing scale and lubricating the skin. Antibiotics are used to treat secondary infections.
The incidence of SA in Maltese is unknown, but it is safe to assume that many cases are initially diagnosed as allergies, hypothyroidism or various skin infections. Since staph infections often occur secondary to SA, a Maltese with SA could conceivably be diagnosed as having only a staph infection when in reality, it may have SA. If your dog has not responded to treatment for another problem, please ask your vet about the possibility of SA.
SA can take many forms, from so severe that the dog is euthanized, to so mild it can go unnoticed. A punch biopsy of the skin is required for diagnosis. SA is often cyclic in nature. The inflammation subsides, the hair grows back somewhat, and then the cycle recurs.
There is also a subclinical form of SA that can be detected only by biopsy.
Therefore, since SA is probably hereditary in Maltese as it is in other breeds, dogs related to SA dogs should be biopsied before breeding them. In Poodles, biopsies are done yearly on dogs as late as age 10 to make sure the condition does not exist. It has been estimated that as many as 9 percent of Standard Poodles are affected by SA, and 42 percent are carriers, up from 7 percent and 38 percent respectively since 1991, showing that the disease is on the rise.
Unfortunately there is no genetic testing yet, so there is no way to determine if a dog is a carrier. In Poodles, a test breeding funded by the Poodle Club of America has shown SA to be inherited as a simple autosomal recessive trait, and the carrier rate in this breed may be as high as 50 percent. There are no sufficient data yet on Maltese to form any such conclusions, but with the help of breeders with affected dogs, a Breed Specific Research Database can be established with the help of the Institute for Genetic Disease Control (GDC). Using databases, the GDC helps breeders determine the genotype of the individual dog, i.e., the dog's ability to transmit a condition to its offspring by studying the phenotypes (actual traits of an individual dog) of relatives, both affected and normal.
The database would gather data in a manner that provides easy transition to the Open Registry if the suspected genetic basis of the disease becomes proven. If there is any indication that Sebaceous Adenitis is in your line, it would be a good idea to contact the GDC to find out how to go about setting up the database. The address is: The Institute for Genetic Disease Control, P.O. Box 222, Davis, CA 95617. The phone and fax number is 530/756-6773.
It would be helpful if all biopsies of Maltese done in the United States were sent to one of the two following veterinary specialists so the data can be centralized. If necessary, your veterinarian can call to request information about the biopsy procedure. The cost of the biopsy is approximately $30. The addresses are:
In the East, Department of Pathology, Michigan State University, East Lansing, MI 48224-1314, phone 517/355-6504.
In the West, Ann M. Hargis, DVM, MS, Dermato Diagnostics, c/o HCS, 1254 West
Pioneer Way, Suite E, Oak Harbor, WA 98277-9907, phone 206/775-6903.
The procedure is quite simple. If there are no clinical signs, the vet will take a minimum of two 6 mm. punch samples from the dog's back between the top of the head and the withers. If there are any scaling or hair loss areas, those areas should be tested too. The area should not be scrubbed or cleaned at all for this procedure. A local anesthetic such as Lidocain into the subcutis is recommended. The biopsy sites are usually closed with one or two sutures. All very simple! It is usually not necessary to anesthetize the dog. The samples are then put in a leak-proof, crush-proof container of 10 percent buffered formalin for mailing.
A biopsy report will show one of four things:
1) No evidence of SA at this time;
2) Evidence of subclinically affected;
3) SA affected with evidence of destruction of sebaceous glands;
4) Equivocal, meaning that some inflammation is present, but may be due to allergy, so retest three to six months later away from seasonal disturbances.
For more information about SA, you can contact The Genodermatosis Research Foundation (GRF). This organization was established in 1990 to provides education and scientific support for research leading to the alleviation of the suffering of our canine friends through understanding, diagnosis, treatment, cure and prevention of heritable skin disease. The GRF publishes a quarterly news letter, Progress in SA Research, which is free. Write to the GRF to have your name added to the mailing list: GRF, 1635 Grange Hall Road Dayton, OH 45432.
With the support of the GRF, I recently conducted a survey to determine what types of treatments dog owners have found to be successful in controlling Sebaceous Adenitis. The survey was made available through a recent GRF newsletter; on the Internet; and it was sent by mail to 17 national breed clubs. Responses came from the United States, Canada, Brazil, Australia, Finland and Japan.
The survey results can be found on the web site: http://webpages.marshall.edu/~drastura/results.html
Or you can send a SASE, business size, to:
5262 West Pea Ridge Rd.
Huntington, WV 25705
and I will send you a copy of the survey results.
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