Living Safely with Food Allergies

What is a food allergy?

A food allergy is an abnormal immune system reaction to certain foods, in which the body mistakenly identifies harmless proteins as dangerous and triggers symptoms that range from mild to life-threatening.

Reaction to certain foods

What Happens in a Food Allergy

Immune system misfire: The body produces antibodies (IgE) against specific food proteins, treating them like harmful invaders.

Chemical release: Exposure causes immune cells to release histamine and other chemicals, leading to symptoms such as hives, swelling, or breathing difficulties.

Rapid onset: Symptoms usually appear within minutes to a few hours after eating the allergenic food.

Why It Matters

Food allergies are not just inconvenient—they can be life-threatening. Understanding the difference between allergy vs. intolerance, recognising symptoms early, and having an emergency plan are critical for safety and prevention.

What are the symptoms of a food allergy?

Food allergy symptoms can range from mild skin reactions to severe, life-threatening anaphylaxis. They usually occur within minutes to a few hours after eating the allergenic food.

Common Symptoms

• Skin reactions: Hives, itching, eczema flare-ups, or swelling of lips, face, tongue, and throat
• Digestive issues: Abdominal pain, nausea, vomiting, or diarrhoea
• Respiratory problems: Wheezing, nasal congestion, coughing, shortness of breath, or throat tightness
• Circulatory effects: Dizziness, fainting, or dangerously low blood pressure

Severe Reaction (Anaphylaxis)

• Rapid swelling of the throat and airways
• Severe drop in blood pressure (shock)
• Difficulty breathing or loss of consciousness
• Requires immediate emergency treatment with epinephrine and medical care

Key Points to Remember

• Even tiny amounts of the allergenic food can trigger symptoms.
• Symptoms can vary from person to person and from one reaction to another.
• Food allergies are often confused with food intolerances, but intolerances do not involve the immune system and are less dangerous.
• Although food allergies can affect adults of any age, children are more likely to experience them.

Also read https://www.drugs.com/health-guide/food-allergy.html.

Practical Main Points

If someone experiences hives, swelling, breathing difficulty, or dizziness after eating, it may signal a food allergy. An allergist should evaluate mild symptoms, and emergency medical attention is necessary for severe ones.

What foods cause allergies?

The foods most likely to cause allergies are milk, eggs, peanuts, tree nuts, soy, wheat, fish, shellfish, and sesame. These nine account for about 90% of all food allergy reactions worldwide.

The “Big Nine” Allergens

• Milk—most common in infants and young children
• Eggs—often outgrown, but can persist into adulthood
• Peanuts—one of the leading causes of severe allergic reactions
• Tree nuts—almonds, walnuts, cashews, hazelnuts, pistachios, etc.
• Soy—common in processed foods and infant formulas
• Wheat—especially in children, though many outgrow it
• Fish—salmon, tuna, cod, etc.
• Shellfish—shrimp, crab, lobster, clams, mussels
• Sesame—increasingly recognized as a major allergen

Expanded List (EU & Global Standards)

In addition to the “Big Nine,” the European Union mandates labeling of 14 allergens to protect consumers:

• Cereals containing gluten (wheat, rye, barley, oats)
• Crustaceans (shrimp, crab, lobster)
• Celery
• Mustard
• Sulphur dioxide and sulphites (used as preservatives)
• Lupin (legume used in flour)
• Molluscs (clams, mussels, squid, octopus)

How are food allergies diagnosed?

Food allergies are diagnosed through a combination of medical history, physical examination, and specialised tests such as skin prick tests, blood tests, elimination diets, and oral food challenges.

Step-by-Step Diagnostic Process

1. Medical History & Symptom Review

• Doctors begin by asking about symptoms, timing, and suspected foods.
• Key details include how quickly symptoms appeared, whether they were reproducible, and their severity (e.g., hives vs. anaphylaxis).
• Family history of allergies or asthma is also considered.

2. Physical Examination

• A general check-up helps rule out other conditions (like intolerances or skin disorders).
• Doctors look for signs such as eczema, wheezing, or chronic digestive issues.

3. Skin Prick Test (SPT)

• A small amount of suspected allergen is placed on the skin, usually the forearm or back.
• The skin is lightly pricked; if a raised bump (wheal) appears, it suggests an allergic reaction.
• Results can be obtained quickly, typically within 15–20 minutes, although there is a possibility of false positives.

4. Blood Tests (Specific IgE Testing)

• These tests measure the level of IgE antibodies against specific foods.
• This method is particularly beneficial in situations where skin tests are not feasible, such as severe eczema or the use of antihistamines.
• Results take longer but help confirm sensitisation.

5. Elimination Diet

• The suspected food is removed from the diet for 2–6 weeks.
• If symptoms improve, the food may be the culprit.
• Reintroduction under medical supervision helps confirm the diagnosis.

6. Oral Food Challenge (Gold Standard)

• The patient consumes increasing amounts of the suspected food under strict medical supervision.
• Doctors monitor for reactions in a controlled setting.
• Considered the most accurate test, but it carries the risk of severe reactions, so it’s only done in specialised clinics.

Important Notes

• Food intolerance vs. allergy: Intolerances (like lactose intolerance) don’t involve the immune system and are not life-threatening.
• Novel diagnostics: Emerging methods include component-resolved diagnostics (testing specific proteins within foods) and basophil activation tests, which may improve accuracy.
• No single test is perfect—diagnosis usually requires combining history, tests, and clinical judgment.

Practical Main Points

If a food allergy is suspected, the safest path is consulting an allergist. Self-diagnosis or unsupervised elimination diets can be risky, especially in children, where nutrition is critical.

How are food allergies treated?

Food allergies are treated primarily by strict avoidance of the allergenic food and prompt management of accidental exposures, including emergency use of epinephrine for severe reactions. There is no cure, but therapies are evolving.

Core Treatment Strategies

Avoidance: 

• The most effective and essential treatment is to completely avoid the allergenic food. This requires careful reading of food labels, awareness of cross-contamination risks, and sometimes avoiding restaurants or processed foods.

Emergency preparedness:

• Epinephrine auto-injectors (e.g., EpiPen): First-line treatment for anaphylaxis, a severe allergic reaction. Patients at risk should always carry one.

Antihistamines: 

• Antihistamines can help with mild symptoms like hives or itching, but they are not sufficient for severe reactions.

Medical alert jewelry: 

• Medical alert jewelry helps others quickly identify the allergy during emergencies.

Emerging & Supportive Therapies

Oral Immunotherapy (OIT): Gradual introduction of small amounts of the allergenic food under medical supervision to build tolerance. Some clinics currently use OIT for treating peanut allergy.

Epicutaneous Immunotherapy (EPIT): Uses skin patches to expose the immune system to allergens in tiny doses.

Sublingual Immunotherapy (SLIT): Allergen extracts are placed under the tongue to desensitize the immune system.

Biologic therapies: Drugs like omalizumab (anti-IgE antibody) are being studied to reduce allergic sensitivity.

Lifestyle & Prevention

Education: Patients, families, and caregivers must learn to recognize early symptoms and act quickly.

School/workplace planning: Allergy action plans ensure teachers, coworkers, and friends know what to do in case of exposure.

Nutrition support: For children, dietitians help ensure balanced nutrition when major foods (like milk or wheat) are excluded.

Key Main Points

• No cure exists yet—management focuses on avoidance and emergency treatment.
• Epinephrine is life-saving and should be used immediately for severe reactions.
• New therapies like oral immunotherapy are promising but not universally available
• Education and planning are as important as medical treatment in preventing complications.

Conclusion

Food allergies represent a serious immune system reaction to certain foods, with symptoms ranging from mild skin irritation to life-threatening anaphylaxis. Food allergies are manageable but require vigilance. With proper diagnosis, avoidance strategies, and emergency planning, individuals can live safely and confidently while research continues to advance toward long-term solutions.