Sebaceous adenitis

From Dog
Revision as of 23:30, 7 November 2012 by WikiSysop (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Characteristic moth-eaten appearance to an Akita with sebaceous adenitis[1]
Characteristic head alopecia and hypotrichosis in a dog with sebaceous adenitis[2]

Sebaceous adenitis is an immune-mediated skin disease of dogs characterized by inflammation of the sebaceous sweat glands of the skin.

In Standard Poodle[3] and Akita breeds, sebaceous adenitis appears to be an autosomal recessive genetic disease of variable expression.

The disease primarily presents in young dogs, although older dogs may be affected and a number of clinical presentations have been reported.

In long-coated breeds (Standard Poodle, Samoyed, Havanese[4], Akita), affected dogs present with a dull brittle coat, alopecia, hypotrichosis, moderate to severe scaling and follicular cast formation, affecting the nasal planum, nasal bridge, top of the head, pinnae, dorsal trunk and tail. Subclinical symptoms may be present, and cycling from sub-clinical to clinical disease is not uncommon. Pruritus and malodor are variable, depending on the presence of secondary bacterial folliculitis and pyoderma.

In short-coated breeds, particularly the Hungarian Vizsla, the disease is characterized by a moth-eaten alopecia, scaling and small nodules on the trunk, head and ears. This form is usually non-pruritic and secondary bacterial folliculitis is rare but has been reported[5].

Diagnosis is usually confirmed by histopathology of biopsied skin samples, which show characteristic lymphoplasmacytic periadnexal nodular granulomatous to pyogranulomatous inflammation of the sebaceous glands. In chronic cases, atrophy or absence of the sebaceous glands may be observed, associated with perifollicular fibrosis and hyperkeratosis.

A differential diagnosis would include hypoadrenocorticism and Demodex spp.

Treatment involves weekly anti-seborrheic shampoos. The use of daily oral retinoids (8,000 - 10,000 IU twice daily)[6], essential fatty acids and evening primrose oil supplements may assist resolution of symptoms in some cases.

If secondary bacterial folliculitis is evident on skin cultures, appropriate broad-spectrum antimicrobials are indicated, particularly cephalexins or amoxycillin/clavulanate.

In severe or chronic cases, the prognosis is guarded, and the use of cyclosporin should be considered (5mg/kg orally every 12 hours) as a pulsing long-term therapy in association with topical therapy[7].

Glucocorticoids such as prednisolone appear to be ineffective in most cases.

References

  1. Akita Friends
  2. Marista Vet
  3. Pedersen NC et al (2012) Genetic characterization of healthy and sebaceous adenitis affected Standard Poodles from the United States and the United Kingdom. Tissue Antigens 80(1):46-57
  4. Frazer MM et al (2011) Sebaceous adenitis in Havanese dogs: a retrospective study of the clinical presentation and incidence. Vet Dermatol 22(3):267-274
  5. Zur G & Botero-Anug AM (2011) Severe ulcerative and granulomatous pinnal lesions with granulomatous sebaceous adenitis in unrelated vizslas. J Am Anim Hosp Assoc 47(6):455-460
  6. Lam AT et al (2011) Oral vitamin A as an adjunct treatment for canine sebaceous adenitis. Vet Dermatol 22(4):305-311
  7. Lortz J et al (2010) A multicentre placebo-controlled clinical trial on the efficacy of oral ciclosporin A in the treatment of canine idiopathic sebaceous adenitis in comparison with conventional topical treatment. Vet Dermatol 21(6):593-601