The most common triggers are:

• Foods: nuts, shellfish, fish, milk, egg, fruits, cereals, etc.

• Medications: antibiotics (such as penicillins), anti-inflammatories, anaesthetics.

• Insect stings: bees, wasps, hornets.

• Latex: gloves, balloons, sanitary equipment.

• Physical exercise, especially if combined with eating certain foods.

• Unknown factors: this is called idiopathic anaphylaxis.

In sensitised individuals, even minimal exposure can trigger a severe reaction within minutes.

Anaphylaxis can affect the skin, respiratory, digestive, cardiovascular and nervous systems. Its most common symptoms are:

Initial symptoms:

• Intense itching on palms, soles, lips, tongue or genitals.

• Reddening of the skin or generalised urticaria.

• Feeling warm, anxious, or weak.

Advanced symptoms:

• Shortness of breath, chest tightness, wheezing.

• Swelling of the lips, tongue, face or throat (angioedema).

• Nausea, vomiting, abdominal cramps, diarrhoea.

• Dizziness, cold sweats, palpitations.

• Drop in blood pressure, confusion or loss of consciousness.

If action is not taken quickly, it may develop into anaphylactic shock, respiratory or cardiovascular arrest.

Anyone allergic to any of the above triggers can develop anaphylaxis. The risk is higher if:

• They have already had a previous anaphylactic reaction.

• They have uncontrolled asthma.

• They are exposed to the allergen again without knowing it.

• It combines factors such as exercise, alcohol, stress, or certain medications.

It can also occur for the first time without a known history of allergy.

The diagnosis is based on an immediate clinical recognition of the patient's symptoms and history. The specialist can then confirm the cause through:

• Skin tests with allergen extracts.

• Specific IgE determination in blood.

• Controlled challenge tests in selected cases.

• Serum tryptase determination (biomarker after a severe reaction).

It is essential to consult an allergist after an anaphylactic reaction, to identify the trigger and prevent future episodes.

Intramuscular adrenaline is the first-line treatment. It should be administered as soon as possible after the onset of the first symptoms.

What to do in the event of an anaphylactic reaction

1. Administer self-injectable adrenaline (in the thigh, through clothing if necessary).

2. Call the emergency services immediately, even if the patient improves.

3. Place the patient on their back with their legs raised.

4. Do not leave the person alone.

5. If there is respiratory or cardiac arrest, initiate resuscitation manoeuvres.

People who are at risk should have a personalised action plan, which includes:

• Always carrying self-injectable adrenaline with them (and knowing how to use it).

• Identifying and avoiding the trigger allergen.

• Using wristbands or ID cards.

• Educating and informing family members, schools, workplaces, etc.

• Regular check-ups with their allergist.

In certain cases, specific immunotherapy may be considered, especially for allergies to insect venoms.

• Check the expiry date of your self-injectable adrenaline every month.

• Always have a spare dose.

• Always check food labels.

• Inform the people you trust about your allergy and how to act.

• Carry a summary of your action plan with you.