Putative cutaneous adverse drug reactions in two dogs

Summary We describe two cases of cutaneous adverse drug reactions (CADR) in dogs. Case 1 presented with erythematous macules with sharply demarcated margins on the abdomen and inguinal area and depigmentation on the lip. Skin lesions appeared after 3 weeks of administration of anti‐epileptic drugs, including phenobarbital. All medications were discontinued, and the skin lesions gradually resolved 4 weeks after discontinuation. Case 2 presented with an erythematous macule‐to‐plaque and erosion on the abdomen and inguinal area after treatment with multiple antibiotics (metronidazole, cefotaxime and marbofloxacin) for 5 days. Histopathological findings revealed large numbers of neutrophils marginating along the endothelium and accumulating around blood vessels. Therefore, the dog was diagnosed with drug‐induced vasculitis, and previously prescribed drugs were discontinued. Two weeks after discontinuation of previously prescribed drugs, no active skin lesions were observed. CADR can be accompanied by a variety of onset times and clinical manifestations, and suspected drugs should be discontinued when CADR is suspected.