Sesame allergy is now recognized as a significant cause of severe allergic reactions among both children and adults.
Tiny in size, the sesame seed can pack a serious allergy punch. Incredibly, the ingestion of just one sesame seed can cause the symptoms of sesame allergy. Sesame is in a family of seeds that also includes poppy seed, flaxseed, sunflower seed, buckwheat, mustard, and pine nut. In the entire family of seeds however, sesame causes the majority of allergic reactions. And, the incidence of sesame allergy is on the rise. This is likely due to the increase in popularity in the use of seeds, including sesame, in the American and Mediterranean diet.
Sesame allergies share many similar properties in terms of the clinical allergy symptoms, severity, and persistence with peanut, tree nut, and shellfish allergies. Despite these similar characteristics, sesame is not “yet” considered one of the “big 8” food allergens. As a result, sesame allergy has not received much attention as a dangerous allergen until recently.
Certain types of diets, most notably the Mediterranean diet, use sesame in a variety of applications, including oils, pastes, confections, baked goods, and cosmetic products. The use of sesame in the United States has rapidly increased in recent years and ranges from use in obvious sources such as hamburger buns, bagels, and other baked goods, to more hidden uses such as lip balm.
However, the increased use of sesame as an ingredient within certain cultures is not the sole cause for a rise in sesame allergy. For instance, a society like India, whose culture uses sesame frequently in the diet, has a low rate of sesame allergy while others, like Israel, have a high rate of allergy. This has led investigators to study the effects of how food processing affects rates of allergy, which likely explains why there are wide cultural variations in rates of peanut and tree nut allergy, as well as sesame allergy.
Sesame and other seeds are plant derived products, and have a number of different proteins that can cause an allergic response. Unfortunately, patients can react to one or all of the different proteins. Most of the allergenic proteins in sesame are shared by many plant derived foods, including peanut, legumes (including soybean), tree nuts, buckwheat, mustard seeds, kiwi, and certain spices.
Recent food allergy surveys in England and Australia found that sesame allergy was more commonly reported than allergy to any tree nut, and an Israeli study found that sesame allergy was more commonly reported than peanut allergy. Compared to the big 8 allergens in the United States (milk, egg, soy, peanut, tree nut, shellfish, fish, wheat), there is far less reported sesame allergy.
Outside of the United States, sesame allergy often occurs by age two, but this is highly influenced by countries that feed their young a sesame rich diet. In the United States, sensitization to sesame is seen in young children, although not to the same extent as in certain countries like Israel. There is data indicating that sesame allergy is less frequent in the 15-20 year old age group. In contrast to low rates in teenagers, sesame allergy is being detected at a higher than expected rate in adults, although it is unknown if these individuals developed new sesame allergy or this was just previously undetected.
As detailed in the preceding paragraph, processing may be the most significant factor influencing sesame allergy, as is the case with tree nuts and peanut. This fact may ultimately influence any conclusion that can be drawn about the natural history of this allergen. As well, there is some difference in the amount of allergen content among the 3 varieties of sesame seeds, with white seeds containing more allergen than the black or brown variants. Regardless, it is abundantly clear that despite protein content differences, all 3 seed types induce allergic reactions in sensitive individuals, and all 3 should be avoided in sesame allergic individuals. Sesame seed, flour, noodle, meal and oil all contain very potent allergen amounts, and there is no safe form or preparation of sesame for a sesame allergic individual to come in contact with.
Sesame is associated with life-threatening anaphylaxis in susceptible individuals! Again, this is very similar to tree nut, peanut, and shellfish allergy, and sesame sensitive individuals are recommended to avoid any amount of contact. Clinical allergy can manifest as eczema, contact dermatitis, asthma, hives, and oral allergy syndrome. Symptoms have been noted to affect the eyes, nose, mouth, lips, tongue, throat, lungs, skin, GI tract, bladder, and the circulation including the heart.
Note: this list is adapted from Gangur et al, Ann Allergy Asthma Immunol 2005, and only provides examples of how sesame can be found in foodstuff.
Like any other food allergy, the treatment of choice for a systemic allergic reaction is epinephrine (EpiPen® or Twinject®) plus an antihistamine. Sesame allergic individuals are at risk for potential life threatening allergic reactions and should have a personal source of self-injectable epinephrine with them at all times. Strict avoidance is very strongly recommended, and care should be taken to avoid potential cross-contamination from preparation surfaces, cooking utensils, pots, pans, plates, and surfaces.
Hand washing after eating is recommended from anyone who dines with any food allergic individual, including sesame allergic. It may be beneficial to avoid certain cultural/ethnic restaurants that may use a lot of sesame in preparing their food. Sesame allergic individuals must take care to avoid unintended exposure through the numerous pharmaceutical and cosmetic use of sesame.
To test for sesame allergy, processed extracts are available for application as a skin test. Because there are several sesame protein allergens that exist, and not all of them have been proven to be captured on skin testing, allergy blood tests (RAST or ImmunoCAP®) are highly recommended if the skin test is negative. It is well established that there is a high degree of cross-reactivity to sesame with peanut, tree nut, legumes, and other seeds, but not all of this is clinically relevant. Many allergists therefore chose to screen sesame allergic individuals with the blood test for the presence of cross reactivity with these other foods, and vice versa.
Sesame is an allergen on the rise in western countries, such as the United States. The European Union and the Canadian Food Inspection Agency have recently put sesame on their allergen watch lists, but the FDA has yet to do the same. This means that sesame does not have to be labeled in “plain English” on packaged goods produced and sold in the United States. Because sesame allergy has not been as well identified and studied as some of the other allergens, more research is needed to define the characteristics of this entity. Very little about the long term outcome is known, except that nearly 80% of sesame allergic individuals taking part in an Israeli study retained their allergy into adulthood.