Customized Open Patch Allergen Testing in a Rhesus Macaque (Macaca mulatta).

An adult rhesus macaque (Macaca mulatta) presented with chronic, progressive dermatitis and alopecia refractory to dietary modification, environmental enrichment, and medical management. A comprehensive dermatologic workup was performed, including the application of a customized open patch allergen testing protocol to evaluate suspected environmental exposures. Patch testing identified a commercial dish soap used in routine sanitation as the likely causative contact allergen. Discontinued use of the product resulted in complete and sustained resolution of clinical signs, with recurrence only following accidental reintroduction of the soap to the facility. To our knowledge, this is the first report describing the use of customized open patch allergen testing to identify a specific contact allergen in a nonhuman primate, highlighting its potential utility as a diagnostic tool in laboratory animal medicine.