Why Do We Have Allergies?

Generally, your immune system protects you from substances that can make you sick. But if you're one whose immune system reacts to something that is harmless to most people, then your body may react with common allergy symptoms such as sneezing, runny nose, and watery eyes. Hundreds of ordinary substances can cause - or trigger - an allergic reaction. Among the most common things that can cause reactions are plant pollen, food, insect stings, mold, dust mites, pet dander, and medications.

Anyone can be affected by allergies, but some people are more prone to them than others. Genetic and environmental factors plat a role in a person's susceptibility to developing allergies. When allergies are common in children, they can occur for  the first time at any age. Some children stop reacting to certain allergens, such as milk and egg, as they grow, but allergies to foods like nuts and fish tend to remain. It's also possible to develop allergies at any age, even as an adult.