atopic allergy vs type I allergic reaction

atopic allergy and type I allergic reaction both are nouns.

Word	Noun	Adjective	Verb	Adverb
atopic allergy	Yes	No	No	No
type I allergic reaction	Yes	No	No	No

As nouns, atopic allergy and type I allergic reaction are synonyms defined as:

atopic allergy and type I allergic reaction: an allergic reaction that becomes apparent in a sensitized person only minutes after contact

Other synonyms of atopic allergy include atopy, immediate allergy.

atopic allergy (noun)	type I allergic reaction (noun)
an allergic reaction that becomes apparent in a sensitized person only minutes after contact	an allergic reaction that becomes apparent in a sensitized person only minutes after contact