atopic allergy vs allergy

atopic allergy and allergy both are nouns.

Word	Noun	Adjective	Verb	Adverb
atopic allergy	Yes	No	No	No
allergy	Yes	No	No	No

As nouns, allergy is a hypernym of atopic allergy; that is, allergy is a word with a broader meaning than atopic allergy:

atopic allergy: an allergic reaction that becomes apparent in a sensitized person only minutes after contact
allergy: hypersensitivity reaction to a particular allergen; symptoms can vary greatly in intensity

Other hypernyms of atopic allergy include allergic reaction.

atopic allergy (noun)	allergy (noun)
an allergic reaction that becomes apparent in a sensitized person only minutes after contact	hypersensitivity reaction to a particular allergen; symptoms can vary greatly in intensity