Risk Factors There is evidence that a combination of genetics and environmental factors may play a role in your allergies. While the exact genetic (inherited) factors are not yet understood, the tendency to allergies, as well as to allergic disease, is linked to heredity. Additionally, people with certain medical conditions have been linked to allergies. People with medical conditions such as asth...

Hundreds or possibly even thousands of ordinary substances (allergens) may trigger an allergic reaction. Common allergens include: Animal dander Drugs/medications such as penicillin Household dust or dust mites Insect stings such as bee stings or fire ant stings Molds Plant pollens such as poison ivy Latex Industrial chemicals Cockroach droppings Fragrances Jewelry Cosmetics Other substances One...