Hello, You have history of allergy and presently you are experiencing lightheadedness. Causes of lightheadedness are commonly dehydration, side effects of certain medications, sudden blood pressure drops, low blood sugar, etc. You should keep yourself well hydrated, take ORS, Electrol and plenty of water. Maintain healthy weight if obese. Cut on carbohydrate, sugar, full fat dairy products, cheese and oily junk food. Stay active, do regular walking and exercises. Medical conditions that can cause lightheadedness are middle-ear disturbance can trigger dizziness in people with allergies, colds, and sinus infections. Lightheadedness may also be indicative of heart disease or stroke. You are suggested to get clinically examined by a GP, get all tests and investigations done so that the pathology can be detected and treatment started. Avoid doing any heavy work, change your position slowly, treat ear and sinus infection. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician