With an eye on the food allergy community as a unique group of consumers since 2008, we're on a quest to find and share ways to continue enjoying the good things in life.

22 August 2012

Food Allergy Questions: Shellfish Allergies at the Beach & Lyme Disease-Food Allergy Connection

Changing weather and seasons raise different challenges and worries for those managing food allergies. Being able to spend more time outside in the warmer temperatures causes scrutiny of sunscreens and bug repellents, and brings up other outdoor health concerns as well. Dr. Wayne Shreffler--a pediatric allergist at the Massachusetts General Hospital for Children (MGHFC)  and Director of the Food Allergy Center at Massachusetts General Hospital--was kind enough to answer some of my summer food allergy questions and has given me permission to share his answers with Food Allergy Buzz readers.

Jennifer B: A number of visitors to Food Allergy Buzz are looking for information about going to the beach with shellfish allergies and whether it's safe to go in the water. Is the shellfish diluted in the ocean so allergic reactions are not a concern?

Dr. Shreffler: Some people with food allergy to shellfish certainly experience contact reactions if they handle things like shrimp, particularly if they are actually cleaning/preparing them. I've certainly had patients where this question has come up, especially if they've had hives after being in the water. I think the risk of such reactions, particularly without any direct exposure to a critter, is very low for a few reasons (below). In fact, I'm generally much more suspicious that someone with hives from being in the ocean has cold-induced urticaria.

The reasons I think the risk of significant reactions is very low are:

The main food allergens are from the muscle protein, which would not be generally present on the outside of or secreted from living organisms.

The dilution factor of any allergens present must be very large (a drop in the ocean as they say). This could be different in a small touch tank or tidal pool)

The route of exposure (skin) is not one generally associated with dangerous systemic reactions.

I do not advise my patients who have shellfish or fish allergies to avoid going to the beach.

Jennifer B: Are those with Lyme Disease at a greater risk of developing food allergies?

Dr. Shreffler: To the best of my knowledge, they are not. I've done a literature search on this and do not find anything. The only connection that comes to mind is that the allergic kind of immune response is thought to have evolved in part to defend us against `ectoparasites' like ticks, and ticks are carriers of Lyme and other diseases. So you might hypothesize that people with strongly allergy-prone immune systems are actually less likely to acquire Lyme, but I know of no data one way or the other.

Fascinating! These questions have been perplexing Food Allergy Buzz readers for some time. Thank you so much Dr. Shreffler and MGHFC for answering our food allergy questions! We're very grateful for all you do!

More information on Dr. Shreffler: He is also the author of a newly published book, Understanding Your Food Allergies and Intolerances: A Guide to Management and Treatment. Please take a moment to view this recent video of Dr. Shreffler explaining the role of food challenges at the Food Allergy Center at Mass General.

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