Hazelnut Allergen Facts, Symptoms, and Treatment
Learn more about common allergic diseases, symptoms, management paradigms, and testing considerations.
Is your patient a candidate for specific IgE testing?
Get detailed information on whole allergens and allergen components.
Ready to test a patient?
Learn more about common allergic diseases, symptoms, management paradigms, and testing considerations.
Is your patient a candidate for specific IgE testing?
Get detailed information on whole allergens and allergen components.
Ready to test a patient?
Allergies to tree nuts such as hazelnuts are common and often severe. These types of allergies typically develop by the age of 2, and the number of tree nuts to which a person is allergic may increase with age.1 Roughly 30 percent of people with a tree nut allergy are allergic to more than one nut. And while peanuts are actually legumes, approximately 20 to 30 percent of those with a peanut allergy are also allergic to one or more types of tree nuts.2 In fact, together, peanuts and tree nuts account for 70 to 90 percent of reported food-related anaphylactic fatalities. Prevalence for tree nut allergy varies by age, region, and the definitions used for diagnosis, but it appears to affect 0.05 to 7.3 percent of the population. And unfortunately, compared to other food allergies, the chances of outgrowing these allergies are lower and restricted to an estimated 10 percent of sensitized individuals.1
The following nine varieties account for the majority of tree nut allergies: walnuts, almonds, pistachios, cashews, pecans, hazelnuts, macadamias, Brazil nuts, and pine nuts.1 Also known as filberts, cobnuts, and hazels, hazelnuts are edible nuts from roughly 15 species of shrubs and trees belonging to the birch family.3 Hazelnuts are often found in pastries and chocolates as well as in nut butters such as Nutella.1 Despite their uses, hazelnuts are the most common tree nut allergy in Europe.2 Plus, in the United States, Western Europe, and Australia, prevalence of hazelnut allergy is 7.2 percent (including those with birch pollen sensitivity) according to one study.4
Hazelnuts can be found in a host of food products such as cookies, pralines, chopped nut blends, nut spreads, cakes, pastries, chocolates, confectionary products, ice creams, breakfast cereals, and breads. Plus hazelnut oil can be used in cooking.7
The following items may contain tree nuts and seeds:4 baked goods, baking mixes, barbeque and pesto sauces, cereals, chocolates, pralines, crackers, dressings, gravies, flavored coffees, frozen desserts, muesli, nougats, almond chicken, pad thai, chili and trout amandines and giandujas (i.e., chocolate blended with hazel nuts), marzipans (i.e., almond paste), almond milks, nut milks, tree nut oils, spreads (e.g., cheese spreads and chocolate nut spreads such as Nutella, which contains hazelnuts), vegetarian dishes, Indian curries, Asian dishes, pastas, liqueurs (e.g., amaretto and Frangelico), natural flavorings and extracts (e.g., pure almond extract), salads, trail mixes, and snack foods.
Also note that the words "natural flavors" and "botanicals" may indicate the presence of nuts or nut flavorings.5 Asian restaurants can be especially problematic because they often use nuts and seeds in their cuisine, and since pans may be used for multiple meal preparations, there's an inherent risk for cross-contamination.8
Nonfood items that may contain tree nuts include:4 bean bags, bird seeds, cosmetics, hair care products, sunscreens, massage oils, and pet foods. In particular, oil from some hazelnuts has been used in food products, perfumes, and soaps.3
Some people with a hazelnut allergy may also experience symptoms when eating other seemingly unrelated foods. This is called cross-reactivity and occurs when your body's immune system identifies the proteins, or components, in different substances as being structurally similar or biologically related, thus triggering a response. The most common cross-reactivities with hazelnuts are plant foods, e.g., tree nuts, fruits, soybeans, vegetables, and legumes.4
If you experience an itchy mouth or ears, scratchy throat, hives on the mouth, or swelling of the lips, mouth, tongue, or throat after eating hazelnuts or other related fresh fruits, raw vegetables, or tree nuts, you may suffer from Pollen Food Allergy Syndrome (PFAS) also called Oral Allergy Syndrome (OAS). This condition is caused by your immune system's reaction to similar proteins, or components, found in foods and pollens.6 It is quite common, as one study suggests that up to 25 percent of children with allergic rhinitis (aka hay fever) also suffer from PFAS.9 Common pollen allergies that could cause OAS when eating hazelnuts include tree (e.g., birch), grass, and weed.4
Hazelnut consists of different types of proteins that all have different characteristics and different levels of risk for causing symptoms. Some people may tolerate hazelnut if it is extensively heated (cooked/roasted), as high temperatures break down the causative proteins. For another patient, hazelnut should be avoided completely since the protein is stable to heat and it could potentially cause a severe event, also called anaphylaxis. Your specific risk profile depends on which proteins in the hazelnut you are allergic to.4
*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.
Since accidental ingestion of tree nuts and cross-contamination between nut species are common, eliminating all tree nuts from your diet simplifies allergy management. But to better determine whether you should avoid all tree nuts or only those to which you're allergic, consult your healthcare provider.1 He or she also may recommend a plan that includes the following.10-13
Your healthcare provider may direct you to take one of the following medications:
If you're with someone who's having an allergic reaction and shows signs of shock, act fast. Look for pale, cool, and clammy skin; a weak, rapid pulse; trouble breathing; confusion; and loss of consciousness. Do the following immediately:
Tree nut allergy symptoms typically occur within minutes of ingestion and can range from hives to anaphylaxis, a potentially life-threatening reaction that impairs breathing and can send the body into shock.2,5 In fact, tree nut allergy accounts for 18 to 40 percent of anaphylaxis cases. This severity is particularly problematic because many people can't recognize tree nuts. In one study, for example, only half of participants with a tree nut allergy correctly identified all forms of the nut to which they were allergic.1
Tree nut allergy symptoms can include:5
Allergic reactions from tree nuts can also come from cross-reactivity to birch pollen in the form of Oral Allergy Syndrome (OAS), aka Pollen Food Syndrome (PFS) and Pollen Food Allerg Syndrome (PFAS).2,6
Symptoms of OAS can include:6
Together with your symptom history, skin-prick testing or specific IgE blood testing can help determine if you are allergic to a particular allergen. If you are diagnosed with an allergy, your healthcare provider will work with you to create a management plan.
*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.
Knowing the proteins, or components, within each allergen that are triggering your symptoms can help guide your management plan. With that in mind, and based on your symptom history, your healthcare provider may suggest something called a specific IgE component test, which can help reveal other pollens and foods you may react to.4
Already have your specific IgE component test results?
Your component test results will include the name of the components (a series of letters and numbers). Your healthcare provider will likely review the results with you, but here you'll find an at-a-glance breakdown you can use as a reference. Simply match the component names to the list below to see what they mean in terms of symptom management.4
nCor a 9, rCor a 14
rCor a 8
rCor a 1
rBet v 2 (Profilin)
MUXF3 (CCD)
Please note that test results should be interpreted by your healthcare provider in the context of your clinical history. Final diagnosis and decisions on further management should be made by your healthcare provider.
*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.