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Sebaceous Adenitis
Sebaceous adenitis is an inflammatory disease directed against the sebaceous glands of the skin. There is a breed predilection for Standard Poodle. Other breeds with a higher incidence include the Akita, Samoyed, and Vizsla. 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.
Signs Clinical signs usually appear in young adult to middle-aged dogs (1 to 5 years). Two different clinical and histopathologic presentations are associated with different breeds including:
Long-coated breeds:
Standard Poodle:
- Symmetrical, partial alopecia of back, neck, and head, nase area, and ears.
- Mild scaling with dull, brittle hair to severe hyperkeratosis
- Secondary bacterial folliculitis is common.
- Intense itch (pruritus) and foul smell may be observed with pyoderma (pus-formed condition of the skin).
Akita:
This condition is most severe in Akitas.
- Generalized, erythematous, papules, pustules, and scales.
- Greasy scaling of the skin
- Generalized partial alopecia.
- Fever and weight loss may be observed.
Samoyed:
- Moderate to severe truncal alopecia and scaling.
- Dull, brittle, and broken hairs.
- Generalized partial alopecia.
- Fever and weight loss may be observed.
Short-coated breeds:
Vizsla:
- Moth-eaten, circular or diffuse alopecia.
- Mild scaling (fine, white, nonadherent).
- Intermittent swelling of muzzle, lips, and eyelids occasionally reported.
- Usually non-itchy. Bacterial folliculitis is rare.
Diagnosis A tentative diagnosis is based on breed and physical findings.
Skin biopsies showing inflammation of the sebaceous glands or a granulomatous skin reaction with destruction of sebaceous glands will indicate sebaceous adenitis.
Treatment 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 (refer to Bacterial Skin Diseases-Canine Pyoderma).
Some dogs with milder clinical signs respond to high doses of essential fatty acids (omega-3 and omega-6), found in many commercial fatty acid supplements and evening primrose oil.
The 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.
Key Terms Used In this Article:
Keratinization is a process by which epithelial cells lose their moisture and are replaced by horny tissu.
Hyperkeratosis is overgrowth of the horny layer of the skin (resulting in calluses and corns.
Pyoderma is a pus-formed condition of the skin
For More Information
1. Color-dilution alopecia in dogs.Kim JH, Kang KI, Sohn HJ, Woo GH, Jean YH, Hwang EK
2. Scott, Miller, Griffin. Small Animal Dermatology, 5th ed., Philadelphia, WB Saunders
3. Nesbitt & Ackerman. Canine & Feline Dermatology, 1st ed., New Jersey, Veterinary Learning Systems
Go Pets America recommends seeking the advice of your local veterinarian for the most appropriate vaccination program and for the diagnosis and treatment of your pet's health problems. For vaccination requirements please contact your state and local licensing authorities.
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