Psoriasiform-lichenoid dermatosis

From Dog
Psoriasiform-lichenoid-like dermatosis in a Springer Spaniel[1]

Psoriasiform-lichenoid dermatosis is a rare skin disease of Springer Spaniels characterized by symmetrical papules, plaques and nodules[2].

The marked breed predilection suggests heritability. The aetiology is not known but this disease may represent an atypical Staphylococcus pseudintermedius infection[3]

The condition is primarily observed in young dogs with lesions on the pinnae, ventral truncal region and genitals[4].

Over time, the lesions progress to hyperkeratotic lesions with adherent crust and keratinaceous debris. Follicular casts may be observed[5].

Chronic cases resemble severe seborrhea with malodor a definite part of the history and Staphylococcal pyoderma may be seen as a secondary factor.

Diagnosis is based on clinical history, symptoms and histopathology. Histologically the epidermis is irregularly acanthotic, often with deep projections into the dermis. Mild hyperkeratosis with focal parakeratosis is frequently present.

Characteristically, there are discrete, often round, intraepidermal pustules which contain eosinophils, neutrophils, or a mixture of both. Pustules progress to well-demarcated, mound-shaped parakeratotic crusts (‘Munro microabscesses’)[6].

A differential diagnosis would include lichenoid keratoses (which is usually observed in other breeds of dog), pinnal alopecia, ringworm, lupus erythematosus and color dilution alopecia.

The disease may take a convoluted course of exacerbations with minimal response to most conventional therapeutics and is usually associated with a guarded prognosis[7].

Resolution may be achieved with prolonged courses of cephalexins such as Cefovecin. The use of cyclosporin, which is used for lichenoid keratoses in other breeds is usually unrewarding[8].

References

  1. Skin Diseases of the Dog and Cat: Clinical and Histopathologic Diagnosis
  2. Gross TL et al (1986) Psoriasiform lichenoid dermatitis in the springer spaniel. Vet Pathol 23(1):76-78
  3. Werner AH (2003) Psoriasiform-lichenoid-like dermatosis in three dogs treated with microemulsified cyclosporine A. J Am Vet Med Assoc 223(7):1013-1016
  4. Diseases of the epidermis in Skin Diseases of the Dog and Cat, 2nd edition (2005), Gross, Ihrke, Walder and Affolter pp. 152-153
  5. DCAVM
  6. Abbey Vet Services
  7. Rosychuk, RA & Luttgen, P (1995) Diseases of the ear. In S.J. Ettinger and E.C. Feldman (eds.) Textbook of Veterinary Internal Medicine. pp:533-550. W.B. Saunders Co., Toronto
  8. Werner AH. Psoriasiform-lichenoid-like dermatosis in three dogs treated with microemulsified cyclosporine A. J Am Vet Med Assoc 2003; 223:1013–1016