A case of eosinophilic granulomatosis with polyangiitis preceded by allergic bullous lesions.

A 62-year-old man with a history of diabetes mellitus was hospitalised with numbness of lower limbs, bullous lesions of the whole body, kidney dysfunction, presence of eosinophils, and elevated antineutrophil cytoplasmic antibodies to myeloperoxidase and anti-bullous pemphigoid 180 antibodies and was diagnosed with mononeuritis multiplex. Kidney and muscle biopsies showed vasculitis with fibrinoid necrosis, whereas skin biopsies showed only blister formation between the epidermis and dermis; a high eosinophilic infiltrate was present in all three tissues. These findings led to a diagnosis of eosinophilic granulomatosis with polyangiitis combined with allergic bullous lesions. Immunohistological examination indicated cytolytic eosinophils and extracellular traps, suggesting the presence of eosinophil extracellular trap cell death (eosinophil ETosis) in diseased tissue.