What is a Lupin Allergy?
What is lupin?
Lupin is a legume that is more frequently consumed and used in the Mediterranean, especially in the form of lupin flour. Lupin allergy is an emerging food allergy, with variable prevalence rates in different geographical regions: It is more prevalent in Mediterranean countries and Australia and less so in North America and Northern Europe .
What are the symptoms of lupin allergy?
Allergic reactions to lupin cause similar symptoms seen with other food allergens and may include hives, oral itching, swelling of the face, tongue or throat, abdominal pain, nausea, vomiting, runny nose or watery eyes, difficulty breathing, cough, wheeze, and cardiovascular symptoms, such as low blood pressure . Anaphylaxis has been reported in the literature as a result of ingestion of commercial products containing ‘hidden’ lupin, and ingestion or inhalation of lupin has also been found to trigger asthma symptoms . The presence of asthma, especially if not well controlled, is a known risk factor for severe allergic reactions, as it is with other common food allergens, so patients with pre-existing asthma must ensure good asthma control and medication compliance. For patients allergic to lupin, contact with lupin flowers in the garden may cause a contact skin reaction.
Is there a link between peanut and lupin allergy?
Lupin allergy can present in both peanut-allergic and non-peanut-allergic patients. Because lupin and peanut belong to the legume family, there is known cross-reactivity. Cross-reactivity, as investigated by rates of skin prick testing, has been reported to be as high as 44%; clinical reactivity rates are lower, but vary widely between studies and different patient populations (5-37%) . Specific allergenic proteins that were found to be structurally similar and responsible for cross reactivity include lupin b-conglutin and peanut Ara h3; lupin b-conglutin and peanut Arah 1; and lupin PR-10 protein and peanut Arah 8 .
As with any food allergy, the evaluation and diagnosis of lupin allergy should begin with a detailed clinical history of a possible IgE-mediated allergic reaction, which would determine if skin prick testing to lupin, performed by an allergist, is warranted. A serum IgE test to lupin may also be performed . Results from skin prick testing and blood testing do not predict how severe a reaction to lupin will be upon ingestion. In some cases, an oral food challenge, which is a supervised feeding of gradually increasing amounts of a lupin-containing food, may be conducted in the allergist’s office to determine whether a patient is able to eat and tolerate lupin. If it is determined that a lupin allergy exists, lupin must be strictly avoided in the diet.
Education to help with allergen avoidance is the first step in management of lupin allergy. Affected individuals should read all food labels prior to eating and be aware of safe practices to avoid cross-contamination. Patients should be taught to identify the signs and symptoms of an allergic reaction and how to treat a reaction. An emergency action plan should be provided listing how to treat a reaction depending on symptoms present and what medications patients should carry with them at all times in case of a reaction  . Anaphylaxis is a life-threatening reaction and should be treated immediately with self-injectable epinephrine; after the use of epinephrine, one should call 911 as further monitoring and treatment may be needed .
What products may contain lupin?
Lupin beans may be eaten whole, boiled or dry and are a common snack in European and Asian countries, but can also be found in America . Lupin beans can be ground into flour or bran and used to add fiber, texture, and protein in food manufacturing   . Lupin is gluten-free and may be found in gluten-free products as a substitute for wheat. Beverages may also contain lupin as a milk or soy alternative .
Lupin may be found in products such as pasta, chocolate spreads, vegetarian sausage, sauces, stews, baked onion rings, salads, lupin hummus spreads, ice creams, antipasto, bread, rolls, biscuits and baked goods (e.g. cookies, cakes). Lupin may be used as a soy substitute in products . Meat and fish dishes may also include lupin. Lupin flour may also be mixed with other flours . Lupin may be a visible ingredient in a product or may be hidden or undeclared on an ingredient label .
Reading ingredient labels: Know the law of the land
When traveling to a different country, be sure to learn about their food allergen labeling laws as they differ among countries. For example, European Union (EU) food allergen labeling rules require that pre-packaged foods sold in the EU clearly describe any of the 14 allergens on their regulatory list, which includes lupin . Required allergen information, including lupin, is also mandatory for non-packaged foods, such as loose foods sold at restaurants or supermarkets in the EU . In the United States, ingredient labeling laws address 8 major food allergens, which do not include lupin . Those allergic to lupin should still read ingredient labels to check for the presence of lupin. Be sure to call food manufacturers with any questions about label content.
Find out more about food allergies.
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This article has been reviewed by Andrew Moore, MD, FAAAAI