allergist
/ˈælərˌdʒɪst/Definitions
1. noun
A medical doctor who specializes in the diagnosis and treatment of allergic diseases and conditions.
“My sister is seeing an allergist to get some help with her seasonal allergies.”
2. noun
A medical specialist who deals with allergies and their treatment.
“The allergist recommended that she try immunotherapy to build up a tolerance to her allergen.”