Tuna allergy
Allergy to tuna.
About tuna allergy
Tuna is a fish and a recognised cause of fish allergy, which often begins in childhood or early adulthood and is usually lifelong. The reaction is IgE-mediated, with the immune system producing antibodies to fish muscle proteins, mainly parvalbumin. Interestingly, tuna and some other large fish contain relatively less parvalbumin than white fish, so a few people allergic to other fish tolerate tuna, but this cannot be assumed and should be checked with a specialist.
Symptoms usually start within minutes and can include an itchy mouth, hives, facial swelling, vomiting, wheeze and, in serious cases, anaphylaxis with breathing difficulty or collapse. Because parvalbumin is shared across species, many people allergic to tuna react to other fish as well. It is important to distinguish true allergy from scombroid poisoning, a reaction to histamine that builds up in poorly stored tuna and mackerel, which causes flushing, headache and rash in anyone who eats the spoiled fish and is not an allergy.
Diagnosis uses skin-prick or specific-IgE blood tests, sometimes with component testing or a supervised challenge to identify which fish are safe. Management centres on avoiding tuna and often other fish, and checking sauces, stocks and processed foods. People at risk carry an adrenaline auto-injector. A severe reaction is a medical emergency: give adrenaline and call 999.
Common triggers
- Tuna 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.