Probable hypersensitivity vasculitis in a dog.

Allergy immunotherapy (hyposensitization) injections or ibuprofen were implicated as causes of hypersensitivity vasculitis in a dog suffering from probable food allergy. The vasculitis was associated with increased complement component, C3, and resulted in deep, ulcerated draining nodules and plaques on the forelimbs, lateral aspects of the thorax, and thighs. Injections had been given as immunotherapy for suspected atopy. Vasculitis, associated with allergy immunotherapy and increased complement component, C3, as well as with nonsteroidal anti-inflammatory drugs, has been reported in human beings.