Broad overview of allergies
An allergy is a reaction the body has to a particular food or substance. Allergies are very common. They're thought to affect more than 1 in 4 people in the UK at some point in their lives. They are particularly common in children. Some allergies go away as a child gets older, although many are lifelong. Adults can develop allergies to things they weren't previously allergic to. Having an allergy can be a nuisance and affect your everyday activities, but most allergic reactions are mild and can be largely kept under control. Severe reactions can occasionally occur, but these are uncommon. Common allergies Substances that cause allergic reactions are called allergens. 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 cow's milk insect bites and stings medication – 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 aren't allergic to them. Symptoms of an allergic reaction Allergic reactions usually happen quickly within a few minutes of exposure to an allergen. They can cause: sneezing a runny or blocked nose red, itchy, watery eyes wheezing and coughing a red, itchy rash worsening of asthma or eczema symptoms Most allergic reactions are mild, but occasionally a severe reaction called anaphylaxis or anaphylactic shock can occur. This is a medical emergency and needs urgent treatment.