Clinical and histopathological features of rostrolateral nasal alar arteriopathy of German shepherd dogs.

Background: Dermal arteritis of the nasal philtrum (DANP) has been described in large-breed dogs.

Objectives: To characterise clinically distinct, discrete fissures of the dorsolateral nasal alae associated with severe bleeding in German shepherd dogs (GSDs).

Animals: Fourteen privately owned GSDs with linear rostrolateral nasal alar fissures and a histopathological diagnosis of nasal vasculopathy.

Materials And Methods: Retrospective analysis of medical records and histological slides.

Results: Mean age of onset was 6 years. Before biopsy, episodic arteriolar bleeding was noted in 11 of the 14 (79%) dogs. Slide analysis revealed enlarged nasal arterioles with expanded vascular tunics and luminal stenosis beneath ulcers. Histopathological lesions consistent with mucocutaneous pyoderma and/or facial discoid lupus erythematosus were present in 5 of the 14 (36%) dogs. Enlarged arterioles stained blue with Alcian blue and Masson's trichrome stains, consistent with deposition of mucin and collagen, respectively. Immunohistochemical stains (neutrophil myeloperoxidase, IBA1, CD3) were performed. CD3 was negative for all dogs, whilst neutrophil myeloperoxidase and IBA1 occasionally demonstrated intramural neutrophils (3 of the 14 dogs, 21%) or histiocytes (1 of the 14 dogs, 7%) in altered vessels, respectively. All dogs underwent medical management and/or surgical excision. Treatments included tacrolimus, prednisone, ciclosporin-modified, pentoxifylline, antimicrobials and doxycycline/niacinamide. No dogs were treated with antimicrobials alone. For seven dogs with long-term follow-up, treatment response was complete in five (71%) and partial in two (29%), with six of the seven (86%) receiving immunomodulatory treatments to maintain remission.

Conclusion And Clinical Relevance: Nasal alar arteriopathy of GSDs shares histopathological changes with DANP. It has characteristic clinical and histopathological features and appears amenable to immunomodulation.