SOS Allergo · I understand & manage
Food allergy: understand it without unnecessary avoidance
Distinguish allergy, sensitisation and intolerance, understand tests and know what you actually need to avoid
In this sheet
3 essential points
A positive test does not equal a food allergy
A positive skin prick test or specific IgE result shows sensitisation. The food, timing, symptoms, amount and circumstances must fit the clinical history.
Avoid what is genuinely dangerous, not an entire food family
An allergy to one food does not automatically mean an allergy to every related food. A food that is already tolerated should not be removed solely because of a positive test.
A generalised reaction may be an emergency
If your personalised plan identifies anaphylaxis: use an adrenaline auto-injector without delay when prescribed and call 15 or 112. An antihistamine does not replace adrenaline.
What is meant by ‘food allergy’?
A food allergy is an immune-system reaction to a normally harmless food. However, not all allergies or food-related conditions work in the same way.
- Situation
- IgE-mediated allergy
- What it means
- A reaction that is usually rapid after eating the food. Hives, swelling, digestive or respiratory symptoms, or anaphylaxis may occur.
- Situation
- Pollen-food allergy syndrome (PFAS)
- What it means
- A cross-reaction between pollens and plant foods, usually rapid and limited to the mouth with certain raw foods.
- Situation
- Food protein-induced enterocolitis syndrome (FPIES)
- What it means
- A usually non-IgE-mediated reaction that is mainly digestive and delayed, with repeated vomiting typically several hours after the food.
- Situation
- Eosinophilic oesophagitis (EoE)
- What it means
- A chronic inflammatory disease of the oesophagus diagnosed in particular by endoscopy and biopsies; it is not a typical immediate IgE-mediated allergy.
| Situation | What it means |
|---|---|
| IgE-mediated allergy | A reaction that is usually rapid after eating the food. Hives, swelling, digestive or respiratory symptoms, or anaphylaxis may occur. |
| Pollen-food allergy syndrome (PFAS) | A cross-reaction between pollens and plant foods, usually rapid and limited to the mouth with certain raw foods. |
| Food protein-induced enterocolitis syndrome (FPIES) | A usually non-IgE-mediated reaction that is mainly digestive and delayed, with repeated vomiting typically several hours after the food. |
| Eosinophilic oesophagitis (EoE) | A chronic inflammatory disease of the oesophagus diagnosed in particular by endoscopy and biopsies; it is not a typical immediate IgE-mediated allergy. |
These are not four severity levels of the same disease: they are different conditions.
Allergy is not intolerance or coeliac disease
- Situation
- Food allergy
- What it means
- The immune system is involved.
- Situation
- Intolerance
- What it means
- For example, poor digestion of lactose causing pain, bloating or diarrhoea, without a milk allergy.
- Situation
- Coeliac disease
- What it means
- An immune-mediated disease related to gluten; it is not an IgE-mediated wheat allergy.
- Situation
- Infection or food poisoning
- What it means
- This can also cause digestive symptoms after a meal without an allergy.
| Situation | What it means |
|---|---|
| Food allergy | The immune system is involved. |
| Intolerance | For example, poor digestion of lactose causing pain, bloating or diarrhoea, without a milk allergy. |
| Coeliac disease | An immune-mediated disease related to gluten; it is not an IgE-mediated wheat allergy. |
| Infection or food poisoning | This can also cause digestive symptoms after a meal without an allergy. |
Symptoms after a meal therefore do not automatically mean ‘food allergy’.
What does an IgE-mediated food allergy look like?
- Skin: hives, redness, itching, swelling.
- Mouth or throat: itching, swelling, change in voice.
- Digestive system: pain, nausea, vomiting.
- Breathing: cough, breathing difficulty, wheezing.
- Circulation or general condition: feeling faint, low blood pressure, loss of consciousness.
Severity is not written in the test result
The size of a skin prick test or the specific IgE value does not, on its own, predict how severe the next reaction will be. These tests may help estimate the likelihood that an allergy exists, but this varies according to the food and context.
Some molecular IgE tests can sometimes refine the diagnosis, for example for peanut, hazelnut or cashew nut, especially when pollen sensitisation is also present. They never replace the clinical history.
My test is positive: should I stop eating this food?
An allergy to one food does not automatically mean that its whole family must be removed. For example, someone allergic to one tree nut does not necessarily need to stop eating other tree nuts they already eat without a problem.
Should ‘all foods’ be tested?
No. Assessment should start from a clinical hypothesis. Testing many foods that are eaten without a problem increases the chance of finding sensitisation without a clinical allergy and then creating unnecessary avoidance.
See also: ‘Preparing for allergy tests’.What if the history and tests are not enough?
An oral food challenge (OFC) is the reference test when the diagnosis remains uncertain. It is performed within an appropriate medical setting and does not mean ‘trying a little at home to see what happens’.
Avoidance: the right amount
Do not test a cooked form, a small amount or a reintroduction on your own after a significant reaction.
Read labels without becoming trapped by them
In the European Union, regulated allergens intentionally present in a food must be clearly declared, and allergens in a prepacked product are emphasised in the ingredients list. Allergen information must also be available for catering and other non-prepacked foods.
Precautionary statements such as ‘may contain traces of...’ or ‘made in a facility that also handles...’ concern a risk of unintended presence and are not mandatory. They should therefore not be turned into the same rule for every patient.
Follow the advice given for your allergy: how to manage precautionary statements should be personalised.
Restaurants, school meals and family or friends: reduce the risk
- name the allergen clearly;
- ask about ingredients when there is any doubt;
- mention the allergy before ordering or eating;
- do not rely only on the appearance of the dish;
- keep your emergency medication accessible when it has been prescribed.
For a child, also see ‘Children with allergies in group settings and PAI’.
Does my child need a very restricted diet?
No. The aim is to preserve as varied a diet as possible around only the necessary avoidance. Dietetic support is particularly useful when several foods are avoided, when a nutritionally important food is involved, or if growth is affected or eating is very selective.
Identifying one allergy does not mean that introducing every other food should automatically be delayed. Tolerated foods should remain in the diet, following advice from the care team.
Food allergy and quality of life
Meals, school, travel, restaurants and celebrations can become sources of anxiety. The aim is not to ‘avoid all risk by avoiding all social life’, but to build realistic safety and increasing independence. Psychological support may be helpful if anxiety becomes significant.
Severity, cofactors and treatments
If the last reaction was mild, will the next one also be mild?
This cannot be guaranteed. The amount, the form of the food, health at the time, insufficiently controlled asthma and certain cofactors may change a reaction.
Cofactors
Exercise, NSAIDs such as ibuprofen or aspirin, and alcohol may increase the risk or intensity of a reaction in some patients. They are not involved in every food allergy.
Asthma and food allergy
Who should carry adrenaline?
Not every patient with a positive food test automatically needs an auto-injector. When a risk of anaphylaxis is identified, the medical team may prescribe one or more auto-injectors and a personalised emergency plan, with training in how to use them.
See ‘Adrenaline auto-injectors’.Antihistamine or adrenaline?
An antihistamine may help some skin or nasal symptoms, but it does not replace adrenaline in anaphylaxis. Your personalised plan takes priority.
Can a food allergy resolve?
Yes, depending on the food, age and situation. Some allergies resolve more often than others. Periodic reassessment may establish whether tolerance has developed and, when appropriate, allow the food to be reintroduced under medical supervision.
Do not let an old allergy label remain for life without reassessment when the situation should be reviewed.
Are there treatments that modify the allergy?
In some specialist settings, oral immunotherapy may be offered, particularly for certain persistent allergies. It must never be improvised at home.
Biological treatments are also being studied or recommended in some international strategies. Their availability and regulatory indications vary by country. In Europe, omalizumab (Xolair) does not currently have a specifically authorised indication for food allergy; its European indications include allergic asthma, chronic rhinosinusitis with nasal polyps and chronic spontaneous urticaria.
Common misconceptions
- Misconception
- ‘My test is positive, so I am allergic.’
- Answer
- No. It first shows sensitisation.
- Misconception
- ‘The higher my IgE, the more severe my next reaction will be.’
- Answer
- It is not that simple.
- Misconception
- ‘I am allergic to one nut, so I must stop all nuts.’
- Answer
- Not automatically if some are already tolerated.
- Misconception
- ‘A mild reaction will always remain mild.’
- Answer
- This cannot be guaranteed.
- Misconception
- ‘An antihistamine is enough for anaphylaxis.’
- Answer
- No.
- Misconception
- ‘Milk allergy means lactose intolerance.’
- Answer
- No.
- Misconception
- ‘Coeliac disease means wheat allergy.’
- Answer
- No.
- Misconception
- ‘Every “may contain” product is forbidden for everyone.’
- Answer
- No. Advice must be adapted to the patient and risk.
| Misconception | Answer |
|---|---|
| ‘My test is positive, so I am allergic.’ | No. It first shows sensitisation. |
| ‘The higher my IgE, the more severe my next reaction will be.’ | It is not that simple. |
| ‘I am allergic to one nut, so I must stop all nuts.’ | Not automatically if some are already tolerated. |
| ‘A mild reaction will always remain mild.’ | This cannot be guaranteed. |
| ‘An antihistamine is enough for anaphylaxis.’ | No. |
| ‘Milk allergy means lactose intolerance.’ | No. |
| ‘Coeliac disease means wheat allergy.’ | No. |
| ‘Every “may contain” product is forbidden for everyone.’ | No. Advice must be adapted to the patient and risk. |
What helps your allergist
Before your appointment, note down if possible:
- the exact food and its form: raw, cooked, processed, drink, powder, sauce, etc.;
- the approximate amount;
- the time it was eaten and the delay before symptoms;
- the exact symptoms and the order in which they appeared;
- the treatment given and its effect;
- the circumstances: exercise, medication, alcohol, infection, etc.;
- whether the food had previously been eaten without a problem and whether it has been eaten again since.
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Key points
Defining the allergy precisely makes care both safer and less restrictive. Correctly avoid what is genuinely dangerous, keep foods that are genuinely tolerated and have the situation reassessed when appropriate.
Main references
- Santos AF, Riggioni C, Agache I, et al. EAACI guidelines on the diagnosis of IgE-mediated food allergy. Allergy. 2023;78(12):3057-3076. doi:10.1111/all.15902. PMID: 37815205.
- Santos AF, Riggioni C, Agache I, et al. EAACI guidelines on the management of IgE-mediated food allergy. Allergy. 2025;80(1):14-36. doi:10.1111/all.16345. PMID: 39473345.
- Sampson HA, Arasi S, Bahnson HT, et al. AAAAI-EAACI PRACTALL: Standardizing oral food challenges - 2024 Update. Pediatr Allergy Immunol. 2024;35(11):e14276. doi:10.1111/pai.14276. PMID: 39560049.
- Service-Public.fr. Quels allergènes doivent être mentionnés sur un produit alimentaire ? Vérifié le 23 octobre 2025. Obligations d’information en France et mentions de précaution.
- European Medicines Agency (EMA). Xolair (omalizumab) - EPAR. Product information updated 8 June 2026. Indications européennes : asthme allergique, rhinosinusite chronique avec polypes nasaux et urticaire chronique spontanée.
This sheet provides general information. It does not make a diagnosis and does not replace an emergency plan, medical consultation or personalised advice from your healthcare professional.
Scientific review: September 2026 · sosallergo.fr