Surgical treatment of bovine nasal granuloma and an allergological exploration

Nasal granuloma in cattle results from inflammation within, and attendant proliferation of, the nasal mucosa possibly in response to an allergic response. However, the relationship between nasal granuloma and allergies remains unclear. Furthermore, severe cases have a poor prognosis because there is currently no effective treatment. Herein, we report three cases of nasal granuloma with severe stertorous breathing that were treated surgically. We also conducted an allergological exploration. Following surgical removal clinical signs did not recur in two of the three cases; however, stertorous breathing persisted in one case, and the cow was sacrificed 4 months later. A histopathological examination revealed that all nasal granulomas featured varying infiltrations of macrophages eosinophils, mast cells, and lymphocytes. The number of mast cells and the proportion of these cells that had degranulated were significantly higher in the granulomas than in normal nasal mucosae. In addition, serum histamine levels were higher in nasal granuloma cases than in normal cows, although serum immunoglobulin E levels were similar, and lymphocyte infiltration in the submucosal layer suggested type I and type IV allergies. Collectively, the results indicate the efficacy of complete surgical curettage for the treatment of allergic nasal granuloma in cattle. Further studies are required to identify the causes and risk factors of allergic nasal granuloma in cows.