Sesame Seed Allergy: The New Food Allergy on The Block

Anand Bhat, MD – Fellowship Trained Allergist & Immunology
Treating Patients at Highland Clinic

As an allergy fellow in training in Shreveport two years ago, I encountered a recent account of a one year old child who had a severe or anaphylactic allergic reaction at a local Mediterranean restaurant. This child, who had never exhibited any kind of allergies previously, developed an immediate rash, vomiting, shortness of breath, and wheezing. It was a severe food allergy, and the child had to go to a nearby emergency room and receive an epinephrine shot.

When presented with this food allergy puzzle, I first asked about the “Big 8” food allergies: milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, and soybeans.  These 8 foods account for the overwhelming majority of food allergies in the United States. However, this child had eaten all of these foods without problems.

After ruling out those 8 traditional food allergens, the next question I asked was about a common food allergen which is recognized and labeled in Australia, Canada, and the European Union but not in the United States; sesame seeds. I reached out to the parents who then brought the child in so I could test him. As I suspected, the culprit of his severe allergic reaction was sesame seeds!

Sesame seeds (which we see on the top of hamburger buns) can come in many other forms.  They are commonly found in veggie burgers and Japanese cuisine. Also, in Mediterranean cuisine, it is made into a concentrated paste called tahini. This paste is found in hummus and as a flavoring or spice in other foods.  The child had eaten at a Mediterranean restaurant the day of his ER visit and presumably had eaten tahini or hummus at that restaurant. He received an epinephrine auto-injector (“Epipen”), and I told his family to completely avoid sesame seeds and sesame products.    

This year, his life, and millions of others, got easier.  Starting January 1, 2023, sesame seed is now considered a major food allergen with the implementation of the Food Allergy Safety, Treatment, Education and Research (FASTER) Act.  This was passed and signed into law in 2021.  Sesame now has to be labeled in plain English by food manufacturers just like the other Big 8 food allergens.  Before 2023, this was a voluntary requirement for manufacturers.  This law is useful for the more than 1 million patients in the United States with sesame allergy including that child here in Shreveport.  This does not impact food already manufactured and sitting in stores or homes before January 1st so it is important to be cautious about reading labels for food from last year.  

Seeing these new labels may leave the public with some questions: Can I have sesame allergy without knowing it? Does this mean eating a few sesame seeds on a hamburger bun can trigger an allergic reaction to the sesame seed allergic patient? What kind of reactions do I need to be looking out for?

Food allergy symptoms usually occur within in the first few minutes or up to one hour after consumption and can have symptoms such as itching, hives, swelling, diarrhea, wheezing, and the potentially life-threatening reaction called anaphylaxis (which is when an immediate rash is followed by either lung, stomach, cardiac, or neurological symptoms.)

However, in this specific case of sesame seed allergies, the patient would need about 600 seeds to elicit a reaction.  That is a lot of seeds that you will be hard pressed to find in most foods, but that high concentration can be found in less than half a teaspoon of tahini sauce.  So, educating yourself on the types of foods and cuisines to watch out for is important. This is similar to those with soy allergy.  Although many foods contain trace amounts of soy, they often are not enough to trigger an allergic reaction the way concentrated soy in the form of soy milk or tofu would.  The “triggering dose” may be well below what is normally encountered in the average American diet. It is also difficult to separate the symptoms of a food intolerance from a food allergy. Food intolerances are common as well and can include, for example, lactose deficiency which is an intolerance to milk but not an allergy to milk.  

Due to these complexities, it is best to have discussions of food allergy with an allergy-immunology specialist.  Testing by skin or blood can be safely performed and interpreted with an allergist.  If the diagnosis is not clear, an oral food challenge can be performed while being observed in the doctor’s office and the allergy may be able to be ruled out altogether.

The best way to find a fellowship-trained allergist is to check the American College of Allergy, Asthma and Immunology’s website at www.acaai.org/find-an-allergist.