Asthma and Allergy > Allergies > Risk Factors

Risk factors

Allergies are fairly common. Both hereditary and environmental factors have been found to play a role.

Children in families where one or both parents have allergies are more likely to develop allergies. Specific allergies usually are not inherited in families, only the tendency to have allergies of some kind. So if your father was allergic to grass pollen, for example, you are no more likely to be allergic to it than another type of pollen. Children who are breastfed are less likely to develop allergies. Children who are exposed to tobacco smoke are more likely to develop asthma.

Research shows that how early in life a child is exposed to common allergens may affect whether he or she develops an allergy to those substances. With dust mites and pet dander, some evidence shows early exposure can prevent allergies; other evidence shows early exposure may cause allergies. Whether a child develops a food allergy may be affected by the age at which the food is first introduced to them. Ask your doctor for the most current information.