Allergy: Cause

and Control Allergy is an immune system reaction to a foreign substance known as an allergen. Allergens are typically harmless to most people, but in some individuals, contact with an allergen can lead to an allergic reaction. Symptoms include sneezing, runny nose, itchy eyes, coughing, and skin rashes. Allergy can be caused by exposure to environmental factors such as pollen or dust, and by certain foods, or drugs. Allergies can be managed through prevention and avoidance, as well as through medications and lifestyle modifications. Early diagnosis and treatment is essential in order to reduce the risks of long-term complications and improve the quality of life of people with allergies.