Q. I know that food allergies can crop up later in life. Is that more likely to happen to people with other allergies or asthma, or is it just as likely to happen to someone with no health issues whatsoever?
Dr. Susan Waserman: Most food allergies start in childhood, but you’re right, they can develop at any time in a person’s life.
Factors that favor the development of food allergy in adults include sensitization to pollens and house dust mites, as well as occupational sensitization (which occurs when people who regularly handle and inhale food become sensitized to it due to repeated exposures).
As well, adults with birch pollen allergy may develop “oral allergy syndrome ,” which leads those affected to experience itchy mouth when they eat certain raw fruits and vegetables. This is the result of cross-reactivity between the food and the pollen.
A couple of interesting points on this topic:
• Those sensitized to house dust mites may end up with shrimp allergy  because both contain the protein tropomyosin.
• Occupational sensitization is also associated with crab and pork allergies.
Dr. Susan Waserman is an allergist and Professor of Medicine in the Division of Allergy and Clinical Immunology at McMaster University in Hamilton, Ont.
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