The best way to prevent an allergic reaction is to avoid the substance that you're allergic to, although this is not always easy or practical.
Below is some practical advice that should help you avoid the most common allergens.
House dust mites
One of the biggest causes of allergies are dust mites, which are tiny insects found in household dust.
You can limit the number of mites in your home by:
choosing wood or hard vinyl floor coverings instead of a carpet
fitting roller blinds that can be easily wiped clean
choosing leather, plastic or vinyl furniture instead of upholstered furniture
cleaning cushions, soft toys, curtains and upholstered furniture regularly, either by washing (at a high temperature) or vacuuming
using tested allergy-proof covers on mattresses, duvets and pillows
using a vacuum cleaner fitted with a HEPA (high efficiency particulate air) filter, as it can trap more dust mites than ordinary vacuum cleaners
regularly wiping surfaces with a damp, clean cloth – avoid dry dusting, as this can spread dust into the air
Concentrate your efforts of controlling dust mites in the areas of your home where you spend the most time, such as the bedroom and living room.
You can find more information on allergies in the home on the Allergy UK website.
It's not pet fur that causes an allergic reaction. Instead, it's flakes of their dead skin, saliva and dried urine.
If you cannot permanently remove a pet from the house, you could try:
keeping pets outside as much as possible, or limiting them to a particular area of the house, preferably an area without carpet
not allowing pets in bedrooms
washing pets at least once a week
regularly grooming pets outside
regularly washing all bedding and soft furnishings pets lie on
using an air filter in rooms where you spend most of your time
increasing ventilation with fans or air conditioning, or by opening windows
If you're visiting a friend or relative with a pet, ask them not to dust or vacuum on the day you're visiting, as this will stir up the allergens into the air.
Taking an antihistamine medicine about an hour before entering a pet-inhabited house can also help reduce your symptoms.
The Allergy UK website has more information about domestic pet allergies.
Tiny particles released by moulds can cause an allergic reaction in some people.
You can help prevent this by:
keeping your home dry and well ventilated
removing any indoor pot plants from your home
not drying clothes indoors, not storing clothes in damp cupboards, and avoiding packing clothes too tightly in wardrobes
dealing with any damp and condensation in your home
avoiding damp buildings, damp woods and rotten leaves, cut grass and compost heaps
By law, food manufacturers must clearly label any foods that contain something that's known to cause allergic reactions in some people.
By carefully checking the label for the list of ingredients, you should be able to avoid an allergic reaction.
People with food allergies most often experience an allergic reaction while eating out at a restaurant.
You can avoid this by:
not relying on the menu description alone (remember, many sauces or dressings could contain allergens)
communicating clearly with the waiting staff and asking for their advice
avoiding places where there's a chance that different types of food could come into contact with each other, such as buffets or bakeries
letting restaurant staff know your dietary requirements, including how severe your food allergy or intolerance is
always checking what allergens are in the dish, even if you have eaten it before, as recipes and ingredients can change
Remember, simple dishes are less likely to contain "hidden" ingredients. If you're not sure about a dish, do not risk it.
Read more about living with a food allergy and get advice from the Food Standards Agency on food allergen labelling.
Pollen allergies, more commonly known as hay fever, are caused when trees and grasses release pollen into the air.
Doctors often call hay fever allergic rhinitis.
Different plants pollinate at different times of the year, so the months you get hay fever will depend on what sort of pollen you're allergic to.
Typically, people are affected during spring (trees) and summer (grasses).
To help keep your hay fever under control, you can:
check weather reports for the pollen count and stay indoors when it's high, if possible
avoid drying clothes and bedding outside when the pollen count is high
wear wraparound sunglasses to protect your eyes
keep doors and windows shut when possible
shower and change your clothes after being outside
avoid grassy areas, such as parks and fields, particularly in the early morning, evening or night, when the pollen count is highest
if you have a lawn, try asking someone else to cut the grass for you
Find out how to prevent hay fever
Insect bites and stings
If you have ever suffered a bad reaction to an insect bite or sting, it's important to take precautions to minimise your risk.
When you're outdoors, particularly in the summer, you could:
cover exposed skin
apply insect repellent
avoid wearing strong perfumes or fragrances, as these can attract insects
Find out how to prevent insect bites and stings
Preventing severe allergies (anaphylaxis)
If you're at risk of experiencing a severe allergic reaction (anaphylaxis), make sure you carry 2 adrenaline auto-injectors with you everywhere.
Wearing a MedicAlert or Medi-Tag medallion or bracelet can make others aware of your allergy in an emergency.
Consider telling your teachers, work colleagues and friends so they can give you your adrenaline injection in an emergency while waiting for an ambulance.