It may be because we’re eating more of it, so we see more cases. It is, after all, a good source of omega-3 fatty acids. But there is evidence that flaxseeds and linseed oil (made from flaxseeds) can elicit an allergic reaction:
Anaphylaxis Caused By Linseed (Flaxseed) Intake, Journal of Allergy and Clinical Immunology, August 1996
Linseed contains potent allergens.6 Exposure to these allergens can occur through the oral route (e.g., linseed infusion; consumption of bread, bakery goods, or milk from cows fed with flax flour; use of cough syrup or laxatives) or through contact with cattle feed or dog food, hair lotion, shampoo, depilatories, insulating materials, carpets, and some linen clothes.5
Our patient did not remember previous contact with linseed, although such contact may have occurred because of the numerous sources of exposure. A positive skin prick test result and specific IgE antibodies indicate a type I hypersensitivity. In our patient, the 22 kd protein seems to be the implicated allergen.
In addition to psyllium,7 linseed should also be considered a possible cause of anaphylaxis from laxatives. We think new cases could arise because of the increasing use of products from health food shops. Flaxseed is also used in some multigrain breads and bakery products.
Look at all the sources of exposure! It isn’t just the actual flaxseeds but commercial products that use them as an ingredient; meat, eggs, and dairy products from animals fed flax (It’s popular right now for hens to be fed flaxseeds to increase the amount of omega-3 in their eggs); cough preparations; laxatives. And there are non-food sources: livestock and pet foods, hair products, insulating materials, furniture and carpets, linen fabrics.
“The Omega-3s in Eggland’s Best Eggs come from the canola oil and flax seeds that are part of the Eggland’s Best unique feed.” –Eggland’s Best
Once you develop a sensitivity, it won’t take much for the immune system to kick in … rash, hives, wheezing, asthma.
Some other references:
Flax Hypersensitiveness, JAMA, 1930
A Report Of Six Cases Of Flax Seed Sensitization With Review Of The Literature, Journal of Allergy, July 1932.
Anaphylaxis From Linseed, European Journal of Allergy and Clinical Immunology, April 2007.