Dr. Ohayon and his team provide a consulting medical service in the field of Allergy and Clinical Immunology to the Southwestern Ontario community. As a consulting service, we work with your family doctor to help you and require their referral. Our office consults on adult and pediatric patients of all ages for various conditions.

We at HamiltonAllergy.ca, our dedicated staff work tirelessly to provide the highest quality services in diagnosing and treating a wide range of allergic conditions. Our office focuses on respiratory allergies involving the nose and chest, allergic skin conditions such as dermatitis and urticaria, multiple presentations of immediate and delayed food allergies, allergic reactions to stings and bites, and adverse drug reactions. Allergic conditions are diagnosed based on your history, examination, allergy testing and, when needed, an allergen challenge to ultimately improve your quality of life. We appreciate your physician referring you to our centre and our involvement in your care.

We recognize that wait times occur.  Our office will work to expedite your consultation.  If it is urgent, please request your family doctors to inform us and we will do the best to see you ASAP.

Meet Dr. Ohayon

Dr. Ohayon completed his Pediatric residency training in 1996 and his fellowship in Allergy & Clinical Immunology, combined children and adults, in 1998. Following his training, he worked as a consultant Pediatrician for the McMaster Children’s Hospital while establishing his consulting Allergy/Immunology practice. He is a Fellow of the Royal College of Physicians and Surgeons, both in Pediatrics and in Clinical Immunology and Allergy. He is  as an Assistant Clinical Professor at McMaster University and is currently on staff at Hamilton Health Sciences and St. Joseph’s Hospital.  

Apart from his clinical duties, Dr. Ohayon teaches medical learners in his office in the field of Allergy and Pediatrics. He teaches medical students at the McMaster DeGroote School of Medicine and is a member of educational committees. He contributes to local continuing medical education as an invited speaker.

Dr. Ohayon’s office participates in research including clinical trials in the field of allergy therapeutics for difficult to control allergic conditions.

Dr. Ohayon maintains fellowship and memberships to Ontario, Canadian, American and European Allergy societies.


  • Allergic skin conditions Clinical Trials on New Allergy Medications

  • Contact allergy

  • Atopic dermatitis

  • Urticaria (Hives)

  • Circumcision

our services

  • Asthma

  • Food allergy

  • Seasonal allergy (hayfever)

  • Immunotherapy

  • Adverse medication reactions

Preparing for my Appointment

For five (5) days before your appointment, you must discontinue antihistamines and over-the-counter cough, cold, or flu medications.  If there are concerns discontinuing your antihistamines, please contact our team.

You MAY continue using asthma puffers, allergy nasal sprays and steroid creams.

If you are on beta-blocker therapy, you will require permission to hold your beta-blocker for (1 to 2) days PRIOR to your appointment. YOU WILL NEED TO RECEIVE APPROVAL FROM YOUR FAMILY DOCTOR TO WITHHOLD YOUR BETA-BLOCKER medication.

A medical consultation can be arranged if you are unable to hold allergy or beta blocker therapy.  Please keep your appointment and Dr. Ohayon will  review your medication status with you.

Appointments and Cancellations

The appointment will be at least 1½ hours.

Cancellations must be made more than 24 hours prior to the appointment time so that we can offer your time to someone else. All missed appointments will be subject to a fee.