What Is Sebaceous Adenitis?
Sebaceous adenitis is an inflammatory disease directed against the sebaceous glands of the skin. What causes sebaceous adenitis is unknown, but speculations include the following:
- Sebaceous gland destruction is a developmental and genetically inherited defect.
- Sebaceous gland destruction is an immune-mediated or autoimmune disease directed against a component of the sebaceous glands.
- The initial defect is a keratinization abnormality with subsequent obstruction of the sebaceous ducts resulting in sebaceous adenitis.
- The sebaceous adenitis and keratinization defects are the result of an abnormality in lipid metabolism affecting keratinization and the production of sebum.
Susceptible Dog Breeds
It has been reported in over 50 breeds, including:
Sebaceous Adenitis vs. Addison Disease
Sebaceous adenitis differs from Addison disease in that it becomes clinically apparent long before significant destruction of the glandular tissues occurs, while signs of Addison’s disease are usually noticed when the adrenal glands have been substantially destroyed, and the dog is in a life-threatening Addisonian crisis. Breeders and owners of Standard Poodles are well aware of this disease. Many poodles get diagnosed because the breed association encourages poodle owners to test their dogs before mating.4 In this breed, the following is usually observed:
- Symmetrical, partial alopecia of back, neck, head, nose area, and ears.
- Mild scaling with dull, brittle hair and hyperkeratosis
- Secondary bacterial folliculitis
- Intense itch and foul-smelling with pyoderma (pus-formed condition of the skin)
Signs In Akita Dogs:
- Red skin, papules, pustules, and scales
- Greasy scaling of the skin
- Partial alopecia
- Fever and weight loss
Signs In Samoyed Dogs:
- Moderate to severe truncal alopecia and scaling
- Dull, brittle, and broken hairs
- Partial alopecia
- Fever and weight loss
- Vizslas may develop moth-eaten, circular or diffuse alopecia, mild scaling (fine, white, nonadherent), intermittent swelling of muzzle, lips, and eyelids, and non-itchy bacterial folliculitis. In Havanese dogs, the ears are most commonly affected.5
Skin biopsies showing inflammation of the sebaceous glands or a granulomatous skin reaction with the destruction of sebaceous glands will indicate sebaceous adenitis.
Milder forms of sebaceous adenitis may be controlled with topical agents directed at removing the scale. Antiseborrheic shampoos (sulfur, salicylic acid, tar) and emollient rinses are used as needed. A topical spray or rinse containing 50% to 75% propylene glycol in water may be applied every 1 to 3 days as needed.
If a bacterial folliculitis is present, shampoos containing an antibacterial agent (benzoyl peroxide, chlorhexidine, ethyl lactate) should be prescribed in addition to appropriate systemic antibiotic therapy. Some dogs with milder clinical signs respond to high doses of essential fatty acids omega-3 and omega-6, which are found in many commercial fatty acid supplements and evening primrose oil.
Lately, treatment with cyclosporine has shown to be beneficial.4 In one study, twenty-five millilitres of cyclosporine (Neoral oral solution, 100 mg/mL) made up to a total volume of 250 mL of liquid with sterile water was applied to the coat once daily followed by an emollient spray. At a 6-week recheck, further, improvement was noted. In some cases, new hair regrowth was apparent.7
Dogs with severe destruction of sebaceous glands have the poorest prognosis for therapeutic response. In general, the response to therapy is quite variable from one patient to the next. The prognosis depends on the severity of the disease. Even though the condition is not lethal, dogs with SA are sometimes euthanized because the treatment is life-long and labor-demanding. A clinically and cosmetically acceptable result is not always obtained.4
- Kim et al. – Color-Dilution Alopecia In Dogs
- Scott, Miller, Griffin – Muller and Kirk’s Small Animal Dermatology
- Nesbitt & Ackerman – Canine & Feline Dermatology
- Tevell et al. – Sebaceous Aadenitis In Swedish Dogs, A Retrospective Study Of 104 Cases
- Frazer et al. – Sebaceous Adenitis In Havanese Dogs: A Retrospective Study Of The Clinical Presentation And Incidence
- Niels C. Pedersen – Center for Companion Animal Health, UC Davis School of Veterinary Medicine. – Determining Whether Risk For Sebaceous Adenitis Of Standard Poodles Is Associated With A Specific DLA Class II Genotype
- S. Paterson – P-71 Successful Therapy Of Sebaceous Adenitis With Topical Cyclosporine In 20 Dogs