Allergy is exagrated response of body to unknown allergen (offender). The allergen could be either Inhalant which is taken in by nose and may reach to lung or it could be ingested as food or as drug. Some allergens are contact allergens responsible for Skin allergies.

Nasal Allergy called as “Allergic Rhinitis”
Nasal & Lung allergies like Asthma are called as “Naso Bronchial Allergies”
“Asthma” is allergy of respiratory tract
Eye Allergy is called “Allergic conjunctivitis” or Spring catarrh
Skin Allergy is called “Atopic Dermatitis”
Skin Hives are called as “Urticaria”
Allergies caused by food are "Food Allergies" Allergies caused by Drugs/Medicine are "Drug Allegies"

All these allergies are “IgE” mediated reaction in blood, hence Total Serum IgE levels are measured, If they are much above the normal, patient is labeled as ‘Atopic’ or ‘Allergic”; such patients need to go for Allergy Test.