FC‐56 Nodular and non‐nodular focal alopecia related to drug injections: a retrospective study of 32 dogs

Abstract

Cutaneous manifestations of idiosyncratic adverse drug reactions are considered uncommon. These manifestations are the result of unexpected drug effects, independent of dose, and are not related to the known mechanism of action of the drug. The pathogenesis is not well understood and may occur through immunologic or nonimmunologic mechanisms. Several clinical cutaneous manifestations of drug reactions are described: anaphylaxis, immune‐complex formation with or without vasculitis, allergic contact dermatitis, erythema multiforme and injection‐site reactions. Thirty‐two dogs were recorded with focal nodular and non‐nodular alopecia. Skin biopsies were taken from 31 cases for histopathological examination. Cytology was done in the remaining case. Based on clinical information and dermatopathological findings, they were divided into five groups. Group 1 included 17 toys dogs (10 French poodles) with non‐nodular circular alopecia associated with rabies vaccination. Group 2 dogs showed a nodular focal panniculitis and included five dogs (three French poodles); three had received a multivalent vaccine and the other two a rabies vaccine. Group 3 dogs included three females (two Maltese terriers) with circular alopecia related to an injectable progestin. Group 4 included three dogs (a Pekinese, a Shih Tzu and a French poodle) that had received glucocorticoid injections. Group 5 was a miscellaneous group of four dogs; two dogs had received injectable ivermectin, another ketoconazole, and there was no clear indication that the fourth dog had received a drug injection. Funding: Self‐funded.