Treating Lip Ulcers in Cats

Feline lip ulcers and eosinophilic plaques are common and often associated with underlying hypersensitivity disorders. In this study, cats with eosinophilic plaques and/or lip ulcers confirmed via skin biopsy were treated with antibiotics or placebo to determine response to amoxicillin trihydrate-clavulanate potassium (Clavamox, pfizerah.com) at 62.5 mg/cat PO q12h for 21 days. Sixteen cats (17 lesions) completed the study. Both lip ulcers and eosinophilic plaques were associated with secondary bacterial infections. Intracellular bacteria were found in at least one oil immersion site and lesional bacteria were found in 12 of 14 skin biopsy sites on histologic examination. Coagulase-positive staphylococci were the most frequently isolated bacterial spp. A 96.2% reduction in mean lesion size was noted in antibiotic-treated cats, as compared with placebo-treated cats with eosinophilic plaques. In the lip ulcer group, cats treated with antibiotics experienced a 42.6% reduction in lesion size. Both eosinophilic plaque and lip ulcer antibiotic-treated groups had significant reductions in mean percentage of fields showing evidence of bacterial infection. Funding provided by Pfizer Animal Health.

CommentaryEosinophilic plaques are most commonly a result of a pruritic trigger, not unlike pyotraumatic dermatitis in dogs. Impression smears can be difficult to interpret because both neutrophilic and eosinophilic infiltrates exist, but bacteria are almost always seen. Careful examination may also reveal concurrent Malassezia overgrowth. Cats that do not respond to antibiotic therapy alone commonly respond to combined treatment with antibiotics and systemic antifungals (eg, itraconazole). It is important to note that medication needs to be given for 21 to 30 days and the underlying trigger must be investigated, otherwise relapse can occur.—Karen Moriello, DVM, DACVD

SourceResponse of feline eosinophilic plaques and lip ulcers to amoxicillin trihydrate-clavulanate potassium therapy: A randomized, double-blind placebo-controlled prospective study. Wildermuth BE, Griffin CE, Rosenkrantz WS. VET DERMATOL 23:110-118, 2012.