An allergy is where your body reacts to something that's normally harmless like pollen, dust or animal fur. The symptoms can be mild, but for some people they can be very serious.

Causes of allergies

Things that cause allergic reactions are called allergens.

Common allergens include:

tree and grass pollen (hay fever)
house dust mites
foods, such as peanuts, milk and eggs (food allergy)
animals, particularly pets like cats and dogs
insect stings, such as bee and wasp stings
certain medicines

Check if it's an allergy

Symptoms of an allergic reaction can include:

a runny nose or sneezing
pain or tenderness around your cheeks, eyes or forehead
coughing, wheezing or breathlessness
itchy skin or a raised rash (hives)
diarrhoea
feeling or being sick
swollen eyes, lips, mouth or throat

Call 999 if:

your lips, mouth, throat or tongue suddenly become swollen
you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
your throat feels tight or you're struggling to swallow
your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
you suddenly become very confused, drowsy or dizzy
someone faints and cannot be woken up
a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised or itchy.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

What happens at your appointment

A GP may arrange some allergy tests or refer you to a specialist allergy clinic to have them.

Tests you may have include:

a skin prick or patch test – where a small amount of the allergen is put on your skin to see if it reacts
blood tests – to check for allergens that may be causing your symptoms
a special diet where you avoid or eat less of a food you might be allergic to, to see if your symptoms get better

Treatments for allergies

Treatments for allergies include:

trying to avoid the thing you're allergic to whenever possible
medicines for mild allergic reactions like antihistamines, steroid tablets and steroid creams
emergency medicines called adrenaline auto-injectors, such as an EpiPen, for severe allergic reactions
desensitisation (immunotherapy) for severe allergic reactions – this involves carefully exposing you to the thing you're allergic to over time, so your body gradually gets used to it and does not react so badly (this should only be done by a medical professional)

Your specialist will give you an allergy management plan that will explain how to manage your allergy.