Pharmacodermy after cephalexin use in a dog: Case report

Abstract

Skin involvement due to an adverse drug reaction (ADR) can be called pharmacodermy and is characterized by a hypersensitivity reaction after the administration of a drug. Some drugs such as vaccines, antimicrobial drugs, non-steroidal anti-inflammatory drugs (NSAIDs), anthelmintics and anesthetic agents are more associated with pharmacodermic reactions. ADRs can be characterized by dermatological signs, which include: exfoliative erythroderma, fixed drug eruption, urticaria, angioedema, vesico-bullous or pustular dermatopathies such as pharmacodermic pemphigus foliaceus, vasculitis, erythema multiforme and toxic epidermal necrolysis, and the patient may also present systemic signs. Diagnosis can be difficult due to the simultaneous use of several drugs, however cytological examination and, mainly, histopathology can be an essential tool in these cases. This paper reports the occurrence of a pharmacodermic reaction in a mixed breed canine after oral use of cephalexin, in which lesions such as papules, pustules, epidermal collars and diffuse desquamation were observed throughout the skin. The diagnosis was made through the history, clinical and histopathological examination. The patient had an excellent recovery after the instituted therapy.