Once you have been diagnosed as having a food allergy, your treatment will involve two important elements:

• providing you with information and advice about the best way to avoid coming into contact with the offending foodstuff (often referred to as an elimination diet), and
• drawing up an emergency care plan that you can use if you accidentally come into contact with the offending food.

Elimination diet

Depending on the type of food that you are allergic to, you may be referred to a dietitian. This is in case eliminating that food from your diet would have an adverse impact on your nutrition.

For example, an allergy to peanuts is unlikely to affect your diet, but an allergy to milk may mean that you will need to find alternative sources of calcium.

It is important that, as part of your elimination diet, you avoid all contact with the offending food. Therefore, as well as avoid eating or drinking the food, you will also need to avoid:

• inhaling the food, for example accidentally sniffing some peanut dust,
• touching the food, and
• cross-contamination.

Cross-contamination is when utensils, such as knives and forks or work surfaces, such as chopping boards, become contaminated with the offending food through shared use.

Reading labels

As part of your elimination diet, it is very important that you read the list of ingredients on the label of any pre-packed food or drink products you buy.

Under European Union law, any pre-packed food or drink that is sold in Ireland must clearly state on the label if it contains the following ingredients:

• celery,
• cereals that contain gluten (including wheat, rye, barley and oats),
• crustaceans (including prawns, crabs and lobsters),
• eggs,
• fish,
• lupin (lupins are common garden plants and the seeds from some varieties are sometimes used to make flour), 
• milk,
• molluscs (including mussels and oysters),
• mustard,
• tree nuts, such as almonds, hazelnuts, walnuts, brazil nuts, cashews, pecans, pistachios and macadamia nuts,
• peanuts,
• sesame seeds,
• soybeans, and
• sulphur dioxide and sulphites (preservatives that are used in some foods and drinks) at levels above 10mg per kg or per litre.

Some food manufacturers also choose to put allergy advice warning labels ('contains xxx') on their pre-packed foods if they contain an ingredient that is known to commonly cause an allergic reaction, such as peanuts, eggs or milk. However, these are not compulsory. If there is no allergy advice box or 'contains' statement on a product, it does not mean that none of the 14 specified allergens are used as ingredients.

Look out for 'may contain' labels, such as 'may contain traces of peanut'. Manufacturers sometimes put this label on their products to warn consumers that they may have become contaminated with another food product during the manufacturing process.

Some non-food products contain allergy-causing food. For example:

• some soaps and shampoos contain soy, egg and tree nut oil
• some pet foods contain milk and peanuts
• some glues and adhesive labels that are used on envelopes and stamps contain traces of wheat

Again, read the labels of any non-food products that you may come into close physical contact with.

Unpackaged food

Currently, unpackaged food does not need to be labelled in the same way as packaged food, and therefore it can be more difficult for the food allergic consumer to know what ingredients are used in a particular dish. Examples of unpackaged food include food sold from:

• bakeries (including in-store bakeries in supermarkets),
• delis,
• salad bars,
• 'ready-to-eat' sandwich shops,
• take-aways, and
• restaurants.

If you have a severe food allergy, you will need to be careful if you want to eat out.

If you wish to eat unpackaged foods, you should follow the advice below.

• Let the staff know. When making a booking at a restaurant, make sure that the staff are aware of your allergy and ask for a firm guarantee that any food you will be served will be free from the food to which you are allergic. If the staff cannot offer such a guarantee, choose another restaurant. As well as informing the chef and kitchen staff who are involved in cooking your food, let waiters and waitresses know so that they understand the importance of avoiding cross-contamination when serving you.
• Read the menu carefully and check for 'hidden ingredients'. Some food types contain other foods that can trigger allergies and which restaurant staff may have overlooked. For example, some desserts contain nuts (e.g. in a cheesecake base), and some sauces contain wheat and peanuts.
• Use the 'taste-test'. Before you begin to eat, take a tiny portion of the food and rub it against your lips to see if you experience a tingling or burning sensation. If you do, it suggests that the food will cause you to have an allergic reaction. However, the 'taste-test' does not always work for all foods, so it should not be used as a substitute for not following the advice above.
• Prepare for the worst. If you follow the advice outlined above, you should not experience any problems, although it is also a good idea to prepare for any eventuality. Always take your anti-allergy medication with you when eating out, particularly if you have been given an auto-injector of adrenalin (see below).

Children

The above advice regarding diet also applies to children with a food allergy. There is some additional advice that you should follow if your child has a food allergy.

• Notify your child's school about their allergy. Depending how severe your child's allergy could be, it may be useful to provide the staff at their school with an emergency action plan in case of accidental exposure. Arrange with the school nurse, or another appropriate staff member, to hold a supply of adrenalin and to administer it if necessary. Food allergy bracelets are also available, which explain how other people can help your child in an emergency.
• Let other parents know. Young children may easily forget about their food allergy and accept food that they should not have when visiting other children. Telling the parents of your child's friends about their allergy should help prevent this.
• Educate your child. Once your child is old enough to understand, it is important that you provide them with clear, simple instructions about what foods to avoid and what they should do in the case of accidental exposure.

Emergency care plan

As part of your emergency care plan, you will usually be given two types of medication that you should keep with you at all times:

• antihistamines, which can be used to manage the symptoms of a mild to moderate allergic reaction, and
• adrenaline, which is used to manage the symptoms of anaphylaxis.

Antihistamines work by blocking the effects of histamine, a protein responsible for most of the symptoms of an allergic reaction.

Adrenaline works by narrowing your blood vessels and countering the effects of low blood pressure, and by opening up your airways to help ease your breathing difficulties. You may be advised to have a device called an adrenaline auto-injector pen. This looks similar to a felt-tip pen and consists of a syringe and a pre-packaged dose of adrenaline.

If you think that you are experiencing an anaphylactic reaction, inject yourself in your thigh or upper arm with the pen before dialling 999 and asking for an ambulance with a paramedic.

There are two auto-injector pens available:

• EpiPen
• Anapen

The adrenaline inside the pen can go out of date, so check the date information on the label and replace it when necessary.