The Leeds Teaching Hospitals NHS Trust

What is an allergy?

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Allergy, defined:

Allergy is defined as an over-reaction of the immune system to a food or substance in the environment (called an allergen), which would be otherwise harmless to most people.

The body recognises the allergen as a threat, and produces antibodies (called IgE) to 'remember' the allergen - similar to how the body fights off a virus.

In an allergic reaction, the antibodies recognise the allergen and trigger the immune system to react.

    Common allergic disorders include: food allergy, allergic rhinoconjunctivitis (hayfever), asthma and eczema.

Common Allergens

The most common childhood allergens you are likely to see include:

  • Foods
  • Grass/tree pollens
  • Dust mites
  • Mould
  • Animal dander
  • Medication
  • Latex
  • Venom

 Symptoms of an Allergic Reaction

When people have allergic reactions, their symptoms can range from mild/moderate, to severe. The symptoms of each category are listed below.

Mild - Moderate Allergic Reaction

  • Swelling of the lips, eyes or face
  • Itchy/tingly lips or mouth
  • Hives (itchy nettle-sting type rash)
  • Nausea/vomiting
  • Sneezing/sniffling

These types of allergic reaction are often managed with an oral antihistamine. It is recommended that you stay with your child following this reaction. We suggest avoiding any vigorous activity for the rest of the day following the allergic reaction. The reason for this is that vigorous activity has the potential to cause a second flare-up of the allergic reaction.

 Severe Allergic Reaction (Anaphylaxis)

  • Swelling of the tongue or throat
  • Noisy breathing
  • Hoarse voice
  • Coughing and/or wheezing
  • Pale and/or floppy/sleepy
  • Collapse and/or unconsciousness

These types of allergic reaction have the potential to be life threatening and must therefore be treated as an emergency. You must dial 999 immediately. We also recommend lying your child flat, or sitting them down.

If your child carries an adrenaline auto-injector pen (EpiPen/Emerade/Jext), give this as per instructions and then dial 999.