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What is anaphylaxis?

Anaphylaxis is the most severe type of an allergic reaction. Symptoms of anaphylaxis may occur within five minutes of exposure to an allergen, but usually within 30 minutes and may affect several parts of the body, causing breathing difficulties and a drop-in blood pressure.

What causes anaphylaxis?

Anaphylaxis is a severe overreaction by your immune system to a substance or food that is not considered harmful to most other people. Substances that cause allergic reactions are called allergens or “triggers”.

Allergic reactions happen because your immune system mistakes a normally harmless substance for a dangerous invader and produces antibodies to fight it. These antibodies release chemicals, such as histamine, that cause the reaction.

The most common allergens are:

  • Animal fur or hair (such as that from cats, dogs, horses, or rabbits)
  • Dust mites
  • Food, especially cow’s milk, eggs, peanuts, seafood, soy, tree nuts (almonds, Brazil nuts, cashews) and wheat
  • Insect stings
  • Latex
  • Medicines
  • Mold
  • Pollen.

An allergen for one person may not cause any problems in another person. There is a link between allergies and asthma.

What are the symptoms of anaphylaxis?

Symptoms of anaphylaxis may include:

  • Abdominal pain, nausea, and vomiting
  • A fall in blood pressure
  • A rapid, weak pulse
  • A widespread skin rash, hives, or welts
  • Difficulty talking or a hoarse voice
  • Loss of consciousness
  • Pale and floppy (young children)
  • Swelling around the mouth, tongue, lips, eyes or throat
  • Severe shortness of breath resulting in difficulty breathing
  • Wheeze or persistent cough.

Should I see a doctor for anaphylaxis?

If you notice somebody with symptoms of anaphylaxis and they are unconscious, place them in the recovery position or allow them to sit if breathing is difficult and call for an ambulance.

People at risk of anaphylaxis should always carry an adrenaline auto-injector with them. Some also may carry an asthma reliever puffer as well, which should be given after the autoinjector.

Emergency medical advice should always be sought after administration of the autoinjector because often a second dose is needed. Anyone experiencing anaphylaxis should be observed for at least four hours in a hospital or emergency clinic. Further treatments, such as antihistamines or corticosteroids may be necessary.

People who have experienced anaphylaxis should try and avoid known allergens. They should also wear a medical alert bracelet (or necklace) that lets others know that they have a serious allergy in case they have a reaction and are unable to communicate.