Whoever initially prescribed the medication—whether it was a pediatrician, internist, family practice physician, or specialist—should be consulted immediately after you experience a negative reaction. If that physician determines that the reaction could be an allergic one, he or she may refer you to an allergist/immunologist.

Allergist

An allergist is a pediatrician or internist who has had at least two years of extra training in the diagnoses and treatment of allergies. The allergist will perform tests, if necessary, to determine the cause of your allergic reaction and then provide guidance in treating any symptoms.