RECOVER Guidelines: First Aid. Evidence, Treatment Recommendations, Knowledge Gap Analysis, and Clinical Guidelines for Acute Allergy and Anaphylaxis in Dogs and Cats.

OBJECTIVE: To systematically evaluate relevant evidence, devise and present treatment recommendations, and identify and present critical knowledge gaps regarding treatment of uncomplicated allergic reaction and anaphylaxis in dogs and cats. DESIGN: Standardized, systematic evaluation of literature pertinent to uncomplicated allergic reaction and anaphylaxis following Grading of Recommendations, Assessment, Development, and Evaluation methodology, modified for two clinical questions. Identified literature regarding prioritized questions in the Population-Intervention-Comparator-Outcome (PICO) format was reviewed independently by Evidence Evaluators, and findings were reconciled by Domain Chairs and Reassessment Campaign on Veterinary Resuscitation (RECOVER) Co-Chairs to arrive at treatment recommendations. This process used an evidence profile worksheet for each PICO question including an introduction, consensus on science, treatment recommendations, justification of recommendations, and knowledge gaps. Treatment recommendations underwent a 4-week comment period among international veterinary stakeholders prior to finalization. These 2026 RECOVER First Aid Guidelines: Acute Allergy and Anaphylaxis summarize treatment recommendations for dogs and cats. SETTING: Transdisciplinary, international collaboration in university, specialty, emergency, and general practice. RESULTS: Six PICO questions pertaining to uncomplicated allergic reaction and anaphylaxis were addressed in this subproject of the RECOVER First Aid Domain. These six PICO questions resulted in 12 treatment recommendations. All recommendations are supported by low or very low quality of evidence (7) or based on expert opinion (5). The RECOVER First Aid Acute Hypersensitivity Reaction Algorithm displays the flow of assessments and treatments for dogs and cats with uncomplicated allergic reaction and anaphylaxis. CONCLUSIONS: These 2026 RECOVER First Aid Guidelines: Acute Allergy and Anaphylaxis present a concise and comprehensive framework for recognizing and treating acute hypersensitivity in dogs and cats. However, meaningful uncertainty remains regarding optimal diagnosis and treatment of these conditions in dogs and cats, and high-priority knowledge gaps are presented to guide collaborative clinical research in this area.