Allergists (also called immunologists) are medical doctors who specialize in the diagnosis and treatment of immune system diseases. They treat people who have conditions such as asthma, eczema, and allergic reactions to food, medicines, insect stings, or environmental agents such as pollen.

Allergists may specialize in treating certain types of conditions, such as food allergies, or they may specialize in treating people in certain age groups, such as pediatric allergists, who treat children. As more is understood about immune system disorders, allergists treat a broader range of conditions caused by immune system problems.

Allergists specializing in clinical immunology and allergy are certified by the Royal College of Physicians and Surgeons of Canada.