Allergies are largely genetic. If a parent has allergies, chances are good the children will too. But that doesn’t necessarily mean there will be symptoms. What is inherited is an immune system that is predisposed to allergic reactions. And sometimes the symptoms don’t emerge until later in life, when exposure to allergens, such as pollen, dust mites or mold, build up over time and reach a critical mass.
Dr. Sublett cites a study of college freshmen who tested positive for the presence of immunoglobulin E, a type of antibody generally associated with allergies, but showed no symptoms. The subjects were checked twice more during their lives.
“Within their college career, about 20% of the students developed some allergies,” Dr. Sublett says. When the researchers checked the subjects again 20 years later, they found that 40% had allergies. The conclusion: It takes environmental exposure for people to develop full-blown allergies, even if they are genetically predisposed, Dr. Sublett says.
Read the full, original story: Why Do Some People Develop Allergies as Adults?
