An allergy is an abnormal reaction of the body's immune system to an allergen or ‘trigger’ substance.
One of the most common allergens is plant pollen, which often causes hay fever. Other allergens include animal hair, dust, mould, and some foods. Common symptoms of a mild allergy may include sneezing, a runny nose, and mild itchy rashes.
What is anaphylaxis?
Anaphylaxis, sometimes called anaphylactic shock, is a severe life-threatening allergic reaction that can develop just seconds after someone comes into contact with the allergen. It is different to the minor allergies caused by pollens and dust as it progresses very quickly (seconds to minutes) and is an emergency. It can affect the whole body, and if it’s not treated quickly enough it could be fatal.
Common triggers of anaphylaxis include bee stings, some foods such as nuts, some medicines such as penicillin, and some natural substances such as latex. Someone at risk of anaphylaxis may know what they are allergic to and carry medication, such as an auto-injector, with them to use in an emergency.
Signs and symptoms
In mild/moderate cases, look for:
a red, itchy rash, or raised area of skin (weals/hives) often around the face and neck
red, itchy, watery eyes
rapid swelling of hands, feet, or face, particularly lips and neck
abdominal pain, vomiting, or diarrhoea
In severe cases, also look for:
difficulty breathing with wheezing or noisy airway
coughing
swelling of tongue and throat with puffiness around eyes
confusion and agitation
signs of shock leading to collapse and unresponsiveness
