Food Allergy & Anaphylaxis
Sesame allergy is a rising problem in the US, though it is not considered one of the top 8 allergens. It is estimated to affect between 0.1-1% overall, including approximately 0.6% of children. Other seeds that are known to cause allergy include pine nut, macadamia nut, flaxseed, sunflower seed, buckwheat, and mustard. In Canada, sesame is considered a major allergen and is required to be labeled. Rates of sesame allergy may differ based on cultural dietary preferences. India, despite high intake of sesame, has low rates of allergy, though in other cultures such as Israel, sesame allergy is more common than peanut allergy.
Sesame consists of several major allergen classes, including seed storage proteins, vicillins, and oleosin. Testing for sesame allergy is potentially tricky. Oleosi, a major sesame allergen, is not detectable on skin testing, though the other major sesame allergens are. Therefore, both skin and serum testing for sesame allergy is highly recommended to avoid any false negative results. There may be differing amounts of allergens contained among the 3 varieties of sesame seeds. White sesame seeds contain the most allergen compared to brown or black seeds. However, all seeds are allergenic. Sesame oil is considered highly allergenic, as is sesame flour.
Individuals with a potential sesame allergy diagnosis should seek a board-certified allergist recommendation for confirmation. Testing should include both skin and blood testing because oleosins are poorly detectable by skin testing. Because sesame is a seed and has evolved from a plant, there are common proteins shared between other seeds, peanut, tree nut, and certain plans (in particular plants used for spices). Common proteins are even noted with carrot and kiwi. As is the case with peanut and tree nut, on allergy tests, the common proteins and similar structures may be responsible for high rates of co-positive tests when assessing for cross-reactivity. Please keep in mind that just having a positive allergy test does not automatically mean that the person is allergic to the item, especially if the person has never eaten the item and developed symptoms. Most of the cross-reactivity has little clinical significance, but always check with your allergist first. In some situations, a food challenge to the item in question may be recommended to determine if these items are safe to eat. However, in others, in particular the cross-reactive item was commonly eaten before the sesame allergy was diagnosed, a challenge is probably not necessary. However, some allergists do recommend total avoidance of potentially cross-reactive foods such as other seeds, peanut and/or tree nuts. The risk of sesame co-processing of these items is not well-described. Please check with your allergist for your specific management plan.
Common Sources of Sesame
- Asian dishes
- Thai dishes
- Hamburger buns
- Pizza crust
- Breads (breadsticks, rolls, bagels)
- Energy bars
- Ice Cream
- Salad Dressing
- Simit (Turkish pretzels)
- Cosmetics (found in many lip balms, ointments, eye products, soaps, oils, creams)
- Pharmaceutical products (check the package insert)
- Nutritional supplements
It is recommended to always carry at least two (2) epinephrine auto-injectors at all times if you have been diagnosed with a sesame allergy. This is in case one misfires or if symptoms return and a second dose is needed. If an epinephrine auto-injector has been used, always seek emergency medical assistance immediately. This is due to the possibility of a biphasic reaction. A biphasic reaction is when a second wave of a reaction occurs, which is usually stronger than the first. It can occur within 2-4 hours and in some cases, up to 8 hours, after the initial reaction. Stay in medical care for at least 4-6 hours. Strict avoidance of sesame and products containing sesame is necessary.
Read all product labels prior to the consumption of a new food product. Before consuming any products, it is important to always read labels carefully to ensure the safety of a food product. In the United States, SESAME IS NOT REQUIRED TO BE LABELED per FALCPA. Sesame is required to be labeled in Canada, however. Some products are well labeled for the presence of sesame, but others are not. Complicating this, in some circumstances, if sesame is used as a flavoring agent and not a primary ingredient, sesame can be referred to as “spice” or “spices”. This particular labeling quirk is a hold-over from some very old laws regarding the labeling of natural flavors, and are admittedly very confusing. As is the case with the FALCPA-required allergens, products with the advisory statements such as “may contain”, “might contain”, or “manufactured in a shared facility that process” on a package for sesame are completely voluntary, and can be ambiguous. The true level of contamination is not declared, and may range from parts per million to micrograms. There may be different risks associated with these levels. It is generally recommended to avoid products with such labeling because of this uncertainty.
Cross-contact from cooking utensils or products like using the same knife or spoon that was used for spreading hummus, or eating lettuce from a salad bar right next to a dish of sesame seeds used as a condiment. Both pose a potential danger. The knife that was used is no longer safe for the sesame allergic individual. A new, clean knife should have be used. As well, the salad bar represents a possible contaminated surface or cross-contaminated food. Lettuce and other salad items that are stored apart from the sesame should be used. Another example is scraping off sesame seeds from a meal and serving it to a sesame allergic individual. It is still unsafe for consumption. A new clean plate, with a safe meal, should be served to the sesame-allergic individual.
Other pages that may be of interest:
Visit FAACT's “CROSS-CONTACT” page to review how to properly clean allergens from hands and surfaces.
Did you know that sesame is one of the few allergens that requires testing both with skin and blood tests to detect all relevant allergens? Oleosin can be missed if just skin testing is used, as it is not well-detected through commercial skin testing extract, but is by standard serum IgE testing.