Substances that cause allergic reactions are called allergen
The more common allergens include :
- grass and tree pollen – an allergy to these is known as hay fever (allergic rhinitis)
- dust mites
- animal dander, tiny flakes of skin or hair
- food – particularly nuts, fruit, shellfish, eggs and cows’ milk
- insect bites and stings
- medicines – including ibuprofen, aspirin and certain antibiotics
- latex – used to make some gloves and condoms
- mould – these can release small particles into the air that you can breathe in
- household chemicals – including those in detergents and hair dyes
Most of these allergens are generally harmless to people who are not allergic to them.
Symptoms of an allergic reaction
Allergic reactions usually happen quickly within a few minutes of exposure to an
They can cause:
- a runny or blocked nose
- red, itchy, watery eyes
- wheezing and coughing
- a red, itchy rash
- worsening of asthma or eczema symptoms
What causes allergies?
Allergies occur when the body’s immune system reacts to a particular substance as
though it’s harmful.
It’s not clear why this happens, but most people affected have a family history of
allergies or have closely related conditions, such as asthma or eczema.
The number of people with allergies is increasing every year.
The reasons for this are not understood, but 1 of the main theories is it’s the result of
living in a cleaner, germ-free environment, which reduces the number of germs our
immune system has to deal with.
It’s thought this may cause it to overreact when it comes into contact with harmless
Main allergy symptoms
Common symptoms of an allergic reaction include:
- sneezing and an itchy, runny or blocked nose (allergic rhinitis)
- itchy, red, watering eyes (conjunctivitis)
- wheezing, chest tightness, shortness of breath and a cough
- a raised, itchy, red rash (hives)
- swollen lips, tongue, eyes or face
- tummy pain, feeling sick, vomiting or diarrhoea
- dry, red and cracked skin
Avoiding exposure to allergens
The best way to keep your symptoms under control is often to avoid the things you’re
allergic to, although this is not always practical.
For example, you may be able to help manage:
- food allergies by being careful about what you eat
- animal allergies by keeping pets outside as much as possible and washing them
- mould allergies by keeping your home dry and well-ventilated, and dealing with
any damp and condensation
- hay fever by staying indoors and avoiding grassy areas when the pollen count is
- dust mite allergies by using allergy-proof duvets and pillows, and fitting wooden
floors rather than carpets