An allergy is where your body's immune system reacts to something typically harmless to people, such as pollen (hay fever), dust, or cat hair. It is also possible to have allergic reactions to specific foods, such as peanuts, shellfish, or wheat.
Allergies are common, with up to 1 in 4 people suffering from allergies in the UK. Symptoms are mostly mild, but the reactions can be severe and even life-threatening for some people.
Allergies are caused by your immune system overreacting to a specific substance, resulting in symptoms such as a rash, swelling, or digestive problems.
Many things that cause allergies (allergens) are common, everyday substances.
While you may not react to an allergen immediately, over time, your body’s immune system learns to recognise these substances and starts to respond to them as though they are harmful. It is your immune system reaction that causes the symptoms of allergies. Allergies are more common in children than adults. While many childhood allergies can improve as the child gets older, allergies can be for life. It is also possible for adults to develop allergies at any point in their lives to things they weren’t previously allergic to.
Substances that cause allergic reactions are known as allergens. While many things can cause an allergic reaction, some are considerably more likely to than others.
Common allergens include:
Symptoms of allergic reactions can vary greatly depending on how you come into contact with the allergen and the severity of your allergy.
Inhaled allergens include pollen (hay fever), dust, and pet fur.
Common examples are mosquito bites and bee stings.
Some people are allergic to chemicals that commonly come into contact with the skin, such as the chemicals in cosmetics, the nickel in jewellery, or the latex found in gloves and condoms.
Food allergies are typically mild, but reactions may be severe or even life-threatening.
Symptoms commonly include::
It is possible to be allergic to any food. However, the Food Standards Agency lists 14 common food allergens. Food manufacturers must clearly label these allergens on food packaging (or the information must be readily available in restaurants, such as on menus or upon request).
Common Food Allergens:
You can find more information on the common food allergens here.
Food intolerances are different from food allergies. A food intolerance is where you can’t digest certain foods properly. However, food intolerances can give rise to similar symptoms to food allergies.
If you think you have an allergy, a doctor may refer you to a specialist. You may also have one of the following tests:
Some people may experience extreme, life-threatening reactions to allergens that can come on very quickly. Such severe reactions are known as anaphylaxis or anaphylactic shock.
Many people with extreme allergies will carry an adrenaline auto-injector with them. If the person is too unwell to inject themselves or tells you how to inject them, you can find instructions on the side of the device.
It would help if you always treated anaphylaxis as a medical emergency. Call 999 immediately, even if the person affected starts to feel better.
You, or the person who’s unwell, may also have a swollen, raised, or itchy rash.
Someone who experiences these symptoms may carry an auto-injector (Epi-Pen). Ask them or check their pockets or bags if they cannot respond. Instructions on how to use them can be found on the side of the device.