Sesame seed allergy is not one of the most common allergies – but it is on the rise and Health Canada has put it on its “priority allergens” list, implicating it as a culprit in many food allergy reactions.
A recent Canadian population survey estimates that .23 per cent of Canadian children have a “probable” allergy to sesame, considerably less than the 1.68 per cent who have a probable allergy to peanuts and the 1.59 per cent to tree nuts.
Yet scientists say sesame allergy  is on the rise, and at a far faster rate than other allergens. Sesame seed allergy is most commonly seen in children, but often carries on into adulthood as well, or can develop in adulthood.
People can also be allergic to many other seeds, including sunflower seed, mustard seed, rapeseed, flaxseed and poppy seed, although these allergies are much less common.
Mustard Seed Allergy
Canada is in the process of adding mustard seed to its list of priority allergens because, even though few people have the allergy, those who do tend to have severe reactions.
Mustard is already included on the European Union’s priority allergen list, but neither sesame nor mustard is currently included among the top allergens in the United States.
Allergies to seeds can be severe, and can cause anaphylaxis, the life-threatening allergic reaction that can affect multiple systems in the body, including the cardiovascular system, the respiratory tract, the skin and the gastrointestinal tract.
Symptoms can include tingling in the mouth, swelling around the face and throat, itchiness, difficulty breathing, abdominal cramping, vomiting and diarrhea, and even a sudden drop in blood pressure, loss of consciousness, or cardiac arrest, which can be fatal. As a result, it is critical that people with serious sesame, mustard or other seed allergies carry an auto-injector (an EpiPen or Twinject) with them at all times.
There are several theories about why seed allergies, and especially sesame allergies, appear to be on the rise in North America. Scientists believe that the increased prevalence of sesame in our diets is at least partly to blame, with foods such as bagels, hummus, halva and other traditionally Middle Eastern and Asian foods, which used to be specialty items, having become mainstream favourites. (In countries such as Israel, where sesame has been a very common food for decades, sesame allergy is very common – even more so than tree nut or peanut.)
Sesame is also commonly added to rice cakes, granola bars, veggie burgers, sauces, soups, salad dressings, margarine and many other foods. Bakeries, as well as Middle Eastern and Asian restaurants are considered especially high-risk for people with sesame allergies.
Sesame seeds are also used in many cosmetics, soaps, hair-care products, and in some medications, sunscreens, ointments and pet foods, so it is relatively difficult to avoid.
See: Where Seeds Hide 
People who are allergic to sesame also may react to poppy seeds, kiwi fruit, hazelnuts and rye grain, as the proteins in these foods are thought to be similar. A recent study has also shown a possible link between peanut allergy and sesame allergy, so the growing prevalence in peanut allergy may actually be playing a role in sesame’s increasing allergy presence.
However, while many peanut-allergic people may test positive for sesame on a skin test, they may still be able to eat it the seeds safely, so it’s important that they discuss the issue with their allergist.
Moreover, people who are allergic to one type of seed may not be allergic to others, or to the cross-reacting foods, so patients should work closely with their physicians to arrive at an accurate diagnosis.
While allergies such as peanuts, tree nuts, wheat and milk are relatively familiar to the general public, fewer people have heard of sesame allergy. This is a concern for allergy practitioners and those living with sesame allergies since others may be less understanding or vigilant around a sesame allergy as opposed to a peanut allergy.
In one study of allergic parents  in Boston, only one in five had understood the allergenic potential of sesame before their children tested positive.
Sesame at the Store
Since sesame is included on the priority allergens list in Canada and Europe,, this means those producing products containing sesame face stricter regulations when it comes to product labeling. As yet, sesame is not considered a priority allergen in the United States.
So in the U.S., it is not mandatory for food manufacturers to declare sesame on labels, and the seed may be hidden in ingredients such as “spices”, “natural flavor” and “tahini”. As a result, people with sesame allergies are encouraged to read product labels very carefully, and to contact food manufacturers when any ingredients are non-specific or unclear.
If you have an allergy to sesame, do not eat any food that may contain sesame, even in trace amounts.
Beware Sesame Oil
People who are allergic to sesame should also carefully avoid sesame oil. Unlike other oils such as corn and peanut oils, which are refined to the point where there is little or no allergenic protein left, sesame oil is made by cold-pressing sesame seeds and is not refined, so retains most of its allergenicity.