Granulomatous mural folliculitis in a dog treated with ciclosporin and methotrexate.

Abstract

BACKGROUND: Canine granulomatous mural folliculitis is a very rare cause of scarring alopecia with unknown pathogenesis. HYPOTHESIS/OBJECTIVES: To report a case of granulomatous mural folliculitis in a dog treated with ciclosporin (Cs) and methotrexate (MTX). ANIMAL: A 13-year-old spayed female Pyrenean shepherd dog with a one month history of scarring alopecia. METHODS AND RESULTS: Histopathological examination revealed a granulomatous and lymphocytic mural and necrotizing folliculitis and furunculosis. Immunochemistry, using antibodies for CD3, CD204, CD206, IBA-1 and CD208, revealed that CD3lymphocytes were infiltrating the outer root sheath along with IBA-1or CD204cells. Ciclosporin (5 mg/kg once daily) and MTX (0.25 mg/kg once weekly then 0.5 mg/kg once weekly) were initiated simultaneously, and Cs was stopped after stabilization of the lesions. The dog's skin disease was stable for six months. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first report of the long-term management of a granulomatous mural folliculitis in a dog. Ciclosporin and MTX appeared to be an effective treatment option. Additional treated cases are needed to assess the effectiveness of MTX in canine immune-mediated diseases.