Kidney bean allergy
Legume allergy to kidney beans.
About kidney bean allergy
Kidney beans are a legume, in the same broad family as peanuts, soya, lentils and peas, and are common in chilli, salads and canned mixed beans. Allergy to kidney beans is not among the most common food allergies but does occur, working through the immediate, IgE-mediated pathway in which the immune system makes antibodies to bean proteins that release histamine and other chemicals on eating. It is worth noting that raw or undercooked kidney beans contain a natural toxin (a lectin) that causes vomiting and diarrhoea in anyone; that is a toxic effect, not an allergy, and thorough cooking removes it.
Genuine allergic reactions usually start within minutes to a couple of hours. Symptoms can include an itchy mouth, hives, swelling, tummy pain, vomiting and, less commonly, wheeze or anaphylaxis, so reactions can occasionally be severe. Because legumes share some proteins, a person allergic to kidney beans may react to other beans or legumes, but such cross-reactivity is variable and being allergic to one legume does not mean you will react to all of them.
Diagnosis is based on your history supported by skin-prick or specific-IgE testing, and sometimes a supervised food challenge, which also helps separate allergy from the toxic effect of undercooked beans. Management means avoiding the beans that trigger you and reading labels on mixed-bean products, ready meals and vegetarian foods. If you are at risk of a serious reaction, carry any prescribed adrenaline auto-injector. A severe reaction is a medical emergency: call 999.
Common triggers
- Kidney bean and products containing it
Symptoms
- Itching or tingling in the mouth
- Hives, itching or eczema
- Swelling of the lips, face, tongue or throat
- Stomach cramps, nausea, vomiting or diarrhoea
- Wheezing or trouble breathing
- In severe cases, anaphylaxis
Avoidance & management
- Read ingredient labels every time
- Ask about ingredients and cross-contamination when eating out
- Keep the food out of shared cooking areas
- Carry prescribed antihistamines or an adrenaline auto-injector
- Seek emergency help for any severe reaction
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.