Allergies themselves are not infectious diseases, but they can create conditions that increase susceptibility to certain infections. Allergies involve the immune system reacting to substances (allergens) that are typically harmless, such as pollen, dust mites, or certain foods.

What They Are: Allergies occur when the immune system overreacts to a substance (allergen), leading to symptoms like sneezing, itching, runny nose, watery eyes, skin rashes, and in severe cases, anaphylaxis.

Common Allergens: These include pollen, pet dander, mold, dust mites, certain foods, insect stings, and medications.