Allergy as you know is hyperrsensitivity to various allergens like dust, pollen, ticks and mites, smoke, fungi spores, animal dander, specific food items like milk, wheat, sea food, etc... We are surrounded by a host of allergens. Not everyone is hypersensitive or allergic but some are due to low immunity.
There are many ways to find out like doing Allergy tests
: Blood and skin tests. Many big hospitals do these tests. You can also consult a Homeopathic
doctor for a Holistic approach towards your problem. The opinion of an Immunologist will also help in case you have some other problems, But , nothing like consulting a doctor for your problems. Meanwhile, some ADL's, mild ot moderate exercises, adequate, well-balanced diet, eating and sleeping on time will help you improve your immunity and overcome your problem. Lat but not the least "Prevention is better than cure" Avoid exposure to allergens!