Nasal hyperkeratosis in Griffon breeds: Clinical, histopathological features and the prevalence in the Swedish population compared to a control group and other brachycephalic breeds.

Background: In the Griffon breeds (GB) nasal hyperkeratosis is common and develops already in early adulthood. Breed-related features and prevalence have not previously been documented.

Hypothesis/objectives: To describe clinical and histopathological features of nasal hyperkeratosis in GB and to document the prevalence.

Materials and methods: Seven GB dogs with nasal hyperkeratosis were examined. Three histopathological samples were analysed. Owners of 107 GB and 493 control dogs completed a questionnaire distributed via social media.

Results: Typical features of nasal hyperkeratosis in GB included varying degrees of dry, firm, excessive proliferation of keratin, affecting the dorsal or dorsolateral aspect of the planum nasale. Histopathology was characterized by severe, lamellar orthokeratotic and focal parakeratotic hyperkeratosis and multiple small serum lakes. Thirty-four of 107 GB dogs (31.8%) and 65 of 493 (13.2%) control dogs had varying degree of nasal hyperkeratosis. No sex predisposition was noted. Median age of onset was 3 years for GB, similar to brachycephalic control dogs whereas non-brachycephalic control dogs had a significantly later age of onset (p = 0.0053).

Conclusions and clinical importance: Idiopathic nasal hyperkeratosis is very common in GB dogs and other brachycephalic breeds with nearly one third being affected, often already a young age.