Why do some people have allergies?

Allergies occur when the immune system overreacts to harmless substances such as pollen, dust, pet dander, or food proteins. The immune system mistakenly identifies them as threats and releases chemicals like histamine, leading to symptoms such as sneezing, itching, or swelling. Genetics play a major role, as children of allergic parents are more likely to develop allergies. Environmental exposure and immune system development in early life also contribute. Antihistamines, immunotherapy, and avoiding triggers help manage symptoms. In severe cases, allergic reactions can cause anaphylaxis, a medical emergency.