Sebaceous Adenitis Testing

 

What is Sebaceous Adenitis?

Sebaceous Adenitis (SA) is a  hereditary skin disease in which the sebaceous glands become inflamed,  often leading to progressive loss of hair. The disease is primarily seen  in Standard Poodles, Akitas, and Samoyeds, although there have been  reported cases in a number of other breeds and mixed breeds as well. The  disease can develop in a wide age range, with age of onset documented  as early as 1 year and as late as 12 years. Males and females appear to  be affected equally. The exact mode of inheritance is unknown.

SA  can be difficult as the symptoms vary by breed, the symptoms are similar  to those of other diseases such as hypothyroidism or allergies, and the  disease can vary greatly in its severity. Visible symptoms include  excessive dandruff or scaling, hair loss, lesions, a musty odor, and  even secondary skin infections. On the other hand, dogs affected with SA  can be subclinical and show no outward signs of the disease.

There  is no DNA test available to genotypically detect SA. Currently,  diagnosis is based on skin biopsy samples, and unfortunately the current  screening method may result in false negatives. Because the age of  onset varies, and since this is only a phenotypic test reflecting a  point in time, retesting is recommended every 1 to 2 years for dogs used  in breeding programs.

 

Treatment Options

SA cannot be cured, but it can be treated  after clearing any secondary skin infections. Treatment usually involves  a topical regimen of frequent bathing and oiling to help loosen and  remove scaling and dead hair. This protocol also helps return lubricants  to the skin due to the absence of the sebaceous glands.

 

Sebaceous Adenitis Exam

The minimum age for registration in the OFA SA database is 12 months.

The  attending veterinarian examines the dog for clinical symptoms of the  disease and notes any findings on the application form. A minimum of two  6mm punch biopsy samples are taken from the skin of the dog’s neck  between the top of the head and the withers. If there are areas of  scaling and hair loss, samples should be taken from those areas.

To  procure the sample, a local anesthetic such as lidocaine may be used.  The area should not be scrubbed or otherwise cleaned, however gentle  clipping of the area may be necessary. The specimen should be placed in a  crush proof container containing formalin in preparation for shipment  to the lab.

In preparing the dog, keep the hair coat clean, groom  gently, and use good flea control practices. Flea bites and other  irritations from matted hair coats or vigorous grooming can cause mild  inflammation and result in equivocal test results.

To avoid  unlikely possibility of irritation from shampooing or topical flea  control, do not shampoo the dog 2 weeks prior to the SA biopsy sampling,  and make sure the biopsy samples are taken a minimum of 3 inches away  from topical flea control product application sites.

The sample,  the completed OFA application, and both the lab fee and OFA fee are  shipped to any of the approved dermapathology labs for evaluation.  Owners and veterinarians procuring the sample are urged to contact the  lab prior to shipping for current fees and any special lab specific  instructions. The lab results are classified as either:

  • Normal No evidence of Sebaceous Adenitis at the time of the evaluation
  • Affected Clinical and biopsy evidence of Sebaceous Adenitis
  • Subclinically Affected The dog has normal skin and hair coat, but has biopsy evidence of SA
  • Equivocal Some inflammation is present, but the cause cannot be determined – retesting recommended in 3 to 6 months