Flaxseed allergy
Allergy to flax/linseed.
About flaxseed allergy
Flaxseed, also called linseed, is the seed of the flax plant and is popular in bread, cereals, smoothies and as a source of omega-3 oils and fibre. Allergy to flaxseed is uncommon but has been documented, and it works through the usual immediate, IgE-mediated pathway: the immune system produces antibodies to flaxseed proteins, and when the seed is eaten these antibodies trigger the release of histamine and related chemicals that cause the symptoms of an allergic reaction.
Reactions generally begin quickly, within minutes to a couple of hours of eating. Reported symptoms range from an itchy mouth, hives and swelling to tummy upset, and in some cases more serious features such as wheezing, throat tightness or anaphylaxis have occurred, so the reaction can occasionally be severe even though most are milder. Because flaxseed is increasingly hidden in health foods, egg-replacers and multi-seed products, accidental exposure is a real risk for sensitised people.
Diagnosis is based on your symptom history, supported by skin-prick or specific-IgE testing and, where needed, a medically supervised food challenge. Management centres on avoidance and careful label-reading, since flax may appear as flaxseed, linseed or ground seed within blends and baked goods. If your allergy team judges you to be at risk of a serious reaction, they may prescribe an adrenaline auto-injector. Any severe reaction involving breathing difficulty or collapse is a medical emergency: call 999 at once.
Common triggers
- Flaxseed 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.