Q: My allergies to trees and grass started when I was a kid and now, in my early 30s, I’ve just recently suffered anaphylaxis to lobster. Plus I tested positive to clams. Are my early pollen allergies likely connected to these new and severe allergies?
Dr. Sharma: Like you, most people with shellfish allergy (an estimated 60 percent) develop the condition as adults. But, it is unlikely that your childhood pollen allergy has predisposed you to a later shellfish allergy.
There is no similarity in the chemical structure of pollen and shellfish allergens.
However, shellfish does contain a protein called tropomysin, which is also found in dust-mite and cockroach allergens. So it is possible that an allergy to shellfish may be more likely in those with pre-existing dust-mite and cockroach allergies.
People with a history of pollen allergy may develop oral allergy syndrome, which causes them to have itching and/or milk swelling of the mouth, lips and throat after eating certain raw fruits and vegetables. This happens because of similarity in the structure of the fruit and vegetable and pollen, which the immune system is already primed to defend against.
While there is no direct relationship between your two forms of allergy, the pollen allergy was an indication, though, that you have had an allergic predisposition.
Dr. Sharma is an allergist, clinical researcher and associate professor of pediatrics. He is Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington D.C. and Director of the Food Allergy Program. He co-authors “The Food Allergy Experts” column in Allergic Living magazine. Questions submitted will be considered for answer in the magazine.Submit a Question View all posts by this medical expert.