Allergies

An allergy is a reaction the body has to a particular food or substance. Allergies are very common, and they're thought to affect more than 1 in 4 people at some point in their lives.

They're especially common in children. Some allergies go away as a child gets older, though many last for life. Adults can also develop an allergy to something that never bothered them before.

Living with an allergy can be a nuisance and can get in the way of your everyday activities. Still, most allergic reactions are mild and can be largely kept under control. Severe reactions can happen now and then, but they're uncommon.

Substances that cause allergic reactions are called allergens. These are the more common ones:

• grass and tree pollen, and 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
• medicine, including ibuprofen, aspirin, and certain antibiotics
• latex, which is used to make some gloves and condoms
• mould, which 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.

An allergic reaction usually comes on fast, often within a few minutes of coming into contact with whatever you're allergic to (the allergen). It 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. Now and then, though, a severe reaction called anaphylaxis, or anaphylactic shock, can happen. This is a medical emergency and needs urgent treatment.

If your pharmacist thinks you might have a mild allergy, they can give you advice and treatment to help manage it. See your pharmacist if you think you or your child might have had an allergic reaction to something. The symptoms of an allergic reaction can also come from other conditions, so your pharmacist can help work out whether an allergy is likely.

If your allergy is particularly severe, or it isn't clear what you're allergic to, the pharmacist may advise you to see your doctor. The doctor may then refer you to an allergy specialist for testing and advice about treatment.

In many cases, the most effective way to manage an allergy is to stay away from the allergen that causes the reaction whenever you can.

If you have a food allergy, for example, check the ingredients list for allergens before you eat anything. The Food Standards Agency has more information about food allergen labelling.

There are also several medicines that help control the symptoms of an allergic reaction, including:

• antihistamines: you can take these when you notice the symptoms of a reaction, or before being exposed to an allergen to stop a reaction occurring
• decongestants: tablets, capsules, nasal sprays or liquids that can be used as a short-term treatment for a blocked nose
• lotions and creams, such as moisturising creams (emollients): these can reduce skin redness and itchiness
• steroid medicine: sprays, drops, creams, inhalers and tablets that can help reduce redness and swelling caused by an allergic reaction

For some people with very severe allergies, a treatment called immunotherapy may be recommended. You are exposed to the allergen in a controlled way over a number of years, so your body gets used to it and doesn't react so severely.

You can read more about treating an allergy and avoiding allergic reactions.

Allergies happen when the body's immune system reacts to a particular substance as though it were harmful. Doctors don't know why this happens. Most people who are affected have a family history of allergies, or they have closely related conditions such as asthma or eczema.

The number of people with allergies is going up every year, and the reasons aren't understood. One of the main theories is that we now live in a cleaner, germ-free environment, so our immune system has fewer germs to deal with. It's thought this may make the immune system overreact when it meets harmless substances.

When you have an allergic reaction, the symptoms usually start within a few minutes of coming into contact with whatever you're allergic to. Sometimes they build up more slowly, over a few hours.

Allergic reactions can be a nuisance and can get in the way of your normal activities, but most are mild. Very occasionally, a severe reaction called anaphylaxis can occur.

These are the common symptoms of an allergic reaction:

• 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

Which symptoms you get depends on what you're allergic to and how you come into contact with it. Pollen, for example, may give you a runny nose. A skin allergy may bring out a rash, and eating something you're allergic to may make you feel sick.

If you or your child might have had an allergic reaction to something, see your pharmacist. They can help work out whether the symptoms come from an allergy or from another condition.

Rarely, an allergy leads to a severe allergic reaction called anaphylaxis, or anaphylactic shock, and this can be life-threatening. It affects the whole body and usually develops within minutes of exposure to something you're allergic to.

Signs of anaphylaxis include any of the symptoms above, as well as:

• swelling of the throat and mouth
• difficulty breathing
• lightheadedness
• confusion
• blue skin or lips
• collapsing and losing consciousness

Anaphylaxis is a medical emergency and needs immediate treatment. Read more about anaphylaxis to find out what to do if it happens.

If you think you have an allergy, tell your pharmacist what symptoms you're having, when they happen, how often they occur and whether anything seems to trigger them. Your pharmacist can give advice and treatment for mild allergies with a clear cause.

If your allergy is more severe, or it isn't obvious what you're allergic to, your pharmacist may advise you to see your doctor. You may need to be referred for allergy testing at a specialist allergy clinic.

The tests that may be carried out are described below.

Skin prick testing is one of the most common tests for allergies.

The doctor puts a drop of liquid on your forearm. The liquid contains a substance you may be allergic to. Then the skin under the drop is gently pricked with a needle. If you are allergic to that substance, an itchy, red bump will appear within 15 minutes.

The test is painless and very safe. Don't take antihistamines before it, because they can interfere with the results.

Doctors may use a blood test for allergies instead of a skin prick test, or alongside it, to help diagnose common allergies. A small sample of your blood is taken and sent for analysis. The laboratory looks for specific antibodies that your immune system makes in response to an allergen.

Doctors use patch tests to find out whether you have contact dermatitis, a type of eczema that can happen when your skin touches an allergen. A small amount of the suspected allergen is put on special metal discs. These are taped to your skin for 48 hours, and the skin is watched for any reaction.

If your doctor suspects you have a food allergy, you may be told to stop eating a particular food for a while to see if your symptoms get better.

After a few weeks, you may be asked to eat that food again, so the doctor can check whether you react to it a second time.

Don't try this on your own. Talk to a qualified doctor or other health professional first.

In a few cases, doctors may also use a test called a food challenge to diagnose a food allergy. You're given the food you think you're allergic to in small amounts at first, and the amount is raised bit by bit while you're watched closely to see how you react.

This test carries more risk than the other tests, because it could cause a severe reaction. But it is the most accurate way to diagnose a food allergy. A food challenge is always done in a clinic, so a severe reaction can be treated straight away if one does develop.

How you treat an allergy depends on what you're allergic to. In many cases a pharmacist can give you advice and treatment.

They'll tell you how to avoid coming into contact with the substance that causes your allergy, and they can recommend medicine to control your symptoms.

Often the best way to keep your allergy symptoms under control is to stay away from the things you're allergic to, though that isn't always practical.

Depending on the allergy, you may be able to help manage it in these ways:

• food allergies by being careful about what you eat
• animal allergies by keeping pets outside as much as possible and washing them regularly
• 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 high
• dust mite allergies by using allergy-proof duvets and pillows, and fitting wooden floors rather than carpets

Antihistamines are the main medicines for allergies. You can take them in two ways:

• as and when you notice the symptoms of an allergic reaction
• to prevent allergic reactions (for example, if you have hay fever, you may take one in the morning when you know the pollen count is high that day)

Which form you use depends on the part of your body your allergy affects. Antihistamines come as tablets, capsules, creams, liquids, eye drops or nasal sprays.

If an allergic reaction has blocked your nose, a decongestant can help for a short time. You can take decongestants as tablets, capsules, nasal sprays or liquids. Don't use them for more than a week at a time, because using them for long periods can make your symptoms worse.

Red, itchy skin from an allergic reaction can sometimes be treated with creams and lotions you can buy without a prescription. These include:

• emollients (moisturising creams), which keep the skin moist and protect it from allergens
• calamine lotion, which helps reduce itchiness
• steroids, which reduce inflammation (see below)

Steroid medicines can help reduce the inflammation that an allergic reaction causes. You can get them in a few different forms:

• nasal sprays and eye drops for an inflamed nose and eyes
• creams for eczema and contact dermatitis
• inhalers for asthma
• tablets for hives (urticaria)

Sprays, drops and weak steroid creams are available without a prescription. Stronger creams, inhalers and tablets need a prescription from your doctor.

Immunotherapy, also called desensitisation, may be an option for a small number of people who have certain severe and persistent allergies and can't control their symptoms with the measures above.

The treatment means being given small doses of the allergen now and then, over several years. You may have it as an injection, or as drops or tablets placed under the tongue.

The injection can only be given in a specialist clinic, under a doctor's supervision, because there is a small risk of a severe reaction. The drops or tablets can usually be taken at home.

The aim is to help your body get used to the allergen, so it doesn't react so severely. This won't necessarily cure your allergy, but it will make it milder, and you can take less medicine.

Some people with severe allergies can have a life-threatening reaction, known as anaphylaxis or anaphylactic shock.

If you're at risk of this, you'll be given special injectors containing a medicine called adrenaline to use in an emergency.

If you develop symptoms of anaphylaxis, such as difficulty breathing, inject yourself in the outer thigh before you seek emergency medical help.

The best way to prevent an allergic reaction is to stay away from whatever you're allergic to, though that isn't always easy or practical. Here is some practical advice that should help you avoid the most common allergens.

Dust mites are one of the biggest causes of allergies. They're tiny insects found in household dust. You can cut down 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, because it can trap more dust mites than ordinary vacuum cleaners
• regularly wiping surfaces with a damp, clean cloth, and avoiding dry dusting, as this can spread dust into the air

Put most of your effort into the areas of your home where you spend the most time, such as the bedroom and living room.

If you have a pet allergy, it's not the fur that sets off the reaction. The cause is flakes of the animal's dead skin, its saliva and its dried urine.

If you can't permanently remove a pet from the house, you could try:

• keeping pets outside as much as possible, or limiting them to one area of the house, preferably an area without carpet
• not allowing pets in bedrooms
• washing pets at least once a week
• grooming pets regularly, and doing it outside
• washing all bedding and soft furnishings where a pet has lain, and doing it regularly
• using an air filter in the rooms where you spend most of your time
• increasing ventilation with fans, air-conditioning or by opening windows

If you're visiting a friend or relative who has a pet, ask them not to dust or vacuum on the day you come, because this stirs the allergens up into the air. Taking an antihistamine medicine about an hour before you go into a house with a pet can also help reduce your symptoms.

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, storing clothes in damp cupboards or 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 known to cause allergic reactions in some people. If you check the label's list of ingredients carefully, you should be able to avoid an allergic reaction.

People with food allergies most often have a 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)
• speaking clearly with the waiting staff and asking for their advice
• avoiding places where 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, don't risk it.

You can read more about living with a food allergy, and about the advice from the Food Standards Agency on food allergen labelling.

Pollen allergies, more commonly known as hay fever, happen 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 when you get hay fever depend on which pollen(s) you are allergic to. Most 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

If you've ever had a bad reaction to an insect bite or sting, take some precautions to lower your risk of it happening again.

When you're outdoors, particularly in the summer, you could:

• cover exposed skin
• wear shoes
• apply insect repellent
• avoid wearing strong perfumes or fragrances, as these can attract insects

If you're at risk of a severe allergic reaction (anaphylaxis), carry two adrenaline auto-injectors with you everywhere you go.

A MedicAlert or Medi-Tag medallion or bracelet can tell other people about your allergy if an emergency happens.

You may want to tell your teachers, work colleagues and friends, so they can give you your adrenaline injection while you wait for an ambulance.