Sebaceous adenitis, also known as glaucomatous sebaceous adenitis or "SA", is an uncommon inflammatory skin disease that leads to the destruction of sebaceous glands.
Sebaceous adenitis (SA) is most common in young to middle-aged dogs (1 to 7 years of age). It is genetically inherited and runs in families of dogs. It is thought to be inherited in Poodles
, Akitas, and Samoyeds. Other breeds at increased risk include Vizlas, Lhasa apso, German shepherd
, and the Bernese mountain dog. It is rare in cats.
The exact cause is not known, but it may be caused by an attack of the immune system against the sebaceous glands responsible for the production of sebum (oil) on the skin. As a consequence, the skin becomes dry and scaly and loses the hair (alopecia). Some dogs may develop skin infection as a consequence of the abnormal skin oil and may become itchy because of the skin infection. Skin infections manifest with odor, papules (red bumps) and excessive shedding. In general, this condition is considered a "cosmetic" problem and does not affect the dogs overall health or lifespan.
The disease starts on top of the head and spreads to the rest of the body. It starts when dogs are one to three years of age and tends to get progressively worse with time.
Screening can be done in dogs belonging to breeds at increased risk for this disease to identify individuals carrying the disease. Biopsies taken from clinically normal skin may already reveal changes suggestive of the condition. Dogs carrying the disease should be excluded from breeding programs due to the genetic nature of this condition.What to Watch For
These disease may appear differently in different pets. Some pets have a generalized condition while other pets have multiple but focal areas of skin affected. Signs may include: Poor condition of hair coat
Progression of hair loss -especially along top of head, back of neck and along the back. Some pets may have ears and legs affected.
Foul musty odor to skin
Itching (in pets with secondary infections)
Other skin diseases may look similar to sebaceous adenitis and must be ruled out by appropriate testing.
Demodicosis is a much more common condition that could also cause hair loss and scaling. For this reason, skin scrapings are done to rule out this type of mange.
Many dogs with sebaceous adenitis have a concurrent skin infection. Cytology – tape impressions of the skin stained to reveal bacteria and yeast – should be done to determine the type and severity of the skin infection.
The final diagnosis of sebaceous adenitis is made by histopathology, so skin biopsies are normally taken. Since the changes seen with this condition may not be present in all the areas, it is important that several biopsies are taken. Stitches are places in the biopsy sites to ensure fast and proper healing.
There is no definite cure for this condition. Long term treatments are generally required to control this disease. However, several topical and systemic treatments can be tried to decrease the clinical signs. Control of secondary infections should be treated with antibiotic therapy.
You may need to bathe your dog several times a week using medicated shampoos to soothe the skin and remove the excessive scaling. Keratolytic shampoos and emollient rinses are often recommended. You will also have to use medicated shampoos (Oxydex) to help speed the recovery from skin infections. Some poodles benefit from weekly baby oil soaks. Topical use of propylene glycol (50 to 75% solution) as a rinse can also be beneficial in some dogs.
Systemic medications are given to eliminate skin infections and normalize the sebum production. The most popular medications used for this condition are retinoids. They are quite expensive and have the potential for serious adverse effects. They are teratogenic, which means they have the potential to cause fetal malformation in pregnant animals, thus they should not be used in breeding animals. As they accumulate in the fat for a long time, the teratogenic effect persists for several months after the discontinuation of the therapy. This type of medication should be tried for at least two months before assessment of the efficacy is made. The most commonly used retinoid is Accutane (isotretinoin).
For dogs that do not respond to retinoids, other medications may be tried. Cyclosporines (Atopica®) have been effective in a few refractory cases. This medication is immunosuppressive, which means it suppresses the reaction of the immune system, and therefore has the potential to increase the risk for bacterial infections. Your dog should be closely monitored for adverse effects including vomiting, diarrhea, liver and kidney disease.
Some dogs benefit from omega-3 and omega-6 fatty acid supplementation. Vitamin A administration at 10,000 IU orally once daily has also been helpful to some dogs.
Antibiotics should be used to treat underlying skin infections.