HeredityAllergy-prone, or atopic, families pass down an immune system quick to make IgE antibodies. One allergic parent: about 50 percent risk. Two: about 75.
Gender and smokeThe Isle of Wight study found risk rises when the same-sex parent is allergic. Smoking in pregnancy and secondhand smoke in infancy raise the odds of allergy and asthma.
EczemaAbout 30 percent of people with eczema develop food allergy, and 50 to 70 percent of children with severe eczema develop asthma.
Between 20 And 25 Percent Of Americans Have Allergies