Rafael “Ray” Firszt, MD

Dr. Rafael “Ray” Firszt is a board-certified allergist and immunologist with more than 15 years of experience diagnosing and treating common and complex allergic and immunologic conditions. He provides comprehensive care for patients with asthma, environmental allergies, food allergies, eczema, angioedema, eosinophilic disorders, immunodeficiencies, mast cell disorders, and other conditions affecting the immune system.

Originally from Montreal, Canada, Dr. Firszt earned his medical degree and Master of Business Administration from McGill University. He completed his pediatric residency at McGill University and a fellowship in pediatric allergy and immunology at Duke University.

Dr. Firszt previously practiced at the University of Utah, where he served as a clinical assistant professor, and at Tanner Clinic. He has contributed to numerous peer-reviewed publications and has extensive experience as a principal investigator for clinical research studies involving asthma, atopic dermatitis, eosinophilic disorders, immunodeficiency diseases, chronic rhinosinusitis, nasal polyps, mastocytosis, and other complex conditions.

Care Philosophy

Dr. Firszt believes effective allergy and immunology care begins with a thorough evaluation and a clear understanding of each patient’s symptoms, health history, and goals. He takes the time needed to investigate challenging conditions, explain findings, and develop an individualized care plan.

His approach combines evidence-based medicine with emerging therapies and clinical innovation. When appropriate, he collaborates with other specialists to ensure patients receive coordinated care that addresses the full scope of their health needs. Through his continued involvement in clinical research, Dr. Firszt stays at the forefront of evolving treatments and may offer eligible patients access to new treatment options.

Above all, Dr. Firszt strives to build long-term partnerships with patients and families, helping them manage symptoms, improve daily life, and feel confident in their care.

Conditions Treated

• Allergic rhinitis and environmental allergies
• Asthma, including severe and eosinophilic asthma
• Atopic dermatitis and eczema
• Chronic hives
• Chronic rhinosinusitis and nasal polyps
• Contact dermatitis and unexplained rashes
• Drug and medication allergies
• Eosinophilic esophagitis and other eosinophilic disorders
• Food allergies and food intolerances
• Hereditary and recurrent angioedema
• Immunodeficiency disorders
• Mast cell disorders and mastocytosis
• Venom and insect-sting allergies

Services Offered

Allergy Testing and Treatment

• Environmental and food allergy skin testing
• Medication allergy testing
• Patch testing
• Venom allergy testing and treatment
• Comprehensive allergy and immunology laboratory testing
• Allergy immunotherapy, including allergy shots
• Sublingual immunotherapy
• Oral immunotherapy for food allergies

Asthma and Advanced Therapies

• Pulmonary function testing
• Fractional exhaled nitric oxide testing
• Biologic injections for severe allergies, asthma, eczema, and angioedema
• Infusion therapies, including immunoglobulin replacement and select intravenous medications
• In-office monitoring and patient education

Additional Diagnostic Services

• Skin biopsies for rashes
• Evaluation and testing for eosinophilic esophagitis
• Hydrogen breath testing
• Virtual visits when clinically appropriate
• Access to qualifying clinical research studies

Education

Fellowship in Pediatric Allergy and Immunology
Duke University, Durham, North Carolina

Residency in Pediatrics
McGill University, Montreal, Quebec, Canada

Doctor of Medicine and Master of Business Administration
McGill University, Montreal, Quebec, Canada

Bachelor of Science in Microbiology and Immunology, Minor in Chemistry
McGill University, Montreal, Quebec, Canada

Diplôme d’études collégiales in Health Science
Marianopolis College, Montreal, Quebec, Canada

Board Certifications

• American Board of Allergy and Immunology
• American Board of Pediatrics
• Royal College of Physicians and Surgeons of Canada, Pediatrics
• Licentiate of the Medical Council of Canada

Professional Memberships

• American Academy of Allergy, Asthma & Immunology
• American College of Allergy, Asthma & Immunology
• American Academy of Pediatrics
• Canadian Paediatric Society

Personal Interests

Outside of the clinic, Dr. Firszt enjoys spending time with his wife and three children. A lifelong hockey enthusiast, he grew up playing the sport and has coached high school hockey at Brighton and Skyline high schools. He also enjoys exploring a variety of foods, with sushi ranking among his favorites.

Dr. Firszt speaks English and French and welcomes new patients at Granger Medical Clinic’s Fairbourne Station location.