• Foods: especially nuts, some kinds of fruit, fish and less commonly spices

   

• Drugs: Especially penicillins, anaesthetic drugs, some intravenous infusion liquids, and things injected during x-rays. Aspirin and other painkillers (called NSAIDs) can produce very similar reactions.

   

• Latex: mainly in rubber latex gloves, catheters, other medical products, but also in many things encountered in daily life. Sufferers are nearly always health care workers, mainly nurses, or have other occupational contact with latex. They may get anaphylaxis from bananas, avocados, kiwi fruit, figs, or other fruits and vegetables including even potatoes and tomatoes.

   

• Bee or wasp (yellow jacket) stings when these cause faintness, difficulty in breathing, or rash or swelling of a part of the body which has not been stung. If you just get a very large swelling of the part of your body which was stung, you are probably not going to have anaphylaxis if stung again.

   

• Unknown: A substantial proportion of sufferers have no cause found despite all efforts, even in the most expert clinics. Doctors call such unexplained attacks 'idiopathic anaphylaxis' The word 'idiopathic' in practice means we don't know the cause. Worrying as it is, death from this is very rare indeed. However, there must be a cause or causes. Some cases are bound to be simple failure to find a cause and I always regard this diagnosis as provisional, but if a recognised allergy specialist has given you this label it is unlikely that another specialist will do any better. The explanation is NOT psychological in the vast majority. So in most cases this is a disease for which medical science has not yet discovered the cause. Some top experts who have studied hundreds of patients with idiopathic anaphylaxis believe that it is a disorder of mast cells, causing them to release histamine and chemicals with similar actions too easily. There is an excellent book on this condition, quite short, and intended for doctors and patients. Title: 'Idiopathic Anaphylaxis', edited by Roy Patterson, Published by OceanSide Publications Inc, Providence, Rhode Island, 1997, ISBN 0-936587-10-5.

   

• Exercise may precipitate such reactions in some ('exercise-induced anaphylaxis'), and so may exercise after food, sometimes apparently irrespective of what the food is, but in other people after specific foods. This is called 'exercise-induced food-dependent anaphylaxis'.

   

• Medicines called beta blockers used for heart disease or high blood pressure can change mild reactions from another cause into severe anaphylaxis because they block the body's main defence against anaphylaxis.

   

• Wrong diagnosis of anaphylaxis: a proportion (about 10%) of people sent to specialists with a diagnosis of anaphylaxis have a mistaken diagnosis and have not had anaphylaxis. If this might be true in your case, it is well worth finding this out as you may be spared unnecessary fear and wrong treatment.

• Minimise the risk by taking great care and being vigilant. If you are food allergic, read labels like Sherlock Holmes: look for the "hidden" allergen. You can easily recognise a packet of peanuts but may miss the word "groundnuts" in tiny print on the side of a tin of curry sauce, or the Latin term arachis used to signify the presence of peanut in pharmaceutical products.
   
• If you are food-allergic, be assertive about asking for detailed information from manufacturers and supermarket staff.
   
• Be particularly careful in restaurants, where proprietors are under no obligation to list ingredients. Question staff very directly. It may be necessary to speak with a senior manager. Some restaurants have ingredient lists available for you to check. You may wish to telephone the restaurant in advance to ensure your allergy is taken seriously.
   
• Be alert to all symptoms and take them seriously. Reach for the adrenaline (epinephrine) if you think you are beginning to show signs of a severe reaction. Do not wait until you are sure. Even if adrenaline is administered, you will still need to get to hospital as soon as possible. Someone must call an ambulance.
   
• Make sure others in your family know how to administer the adrenaline kit - and when. Do not be frightened of adrenaline. It is a well-understood drug. The dose you will administer has very few side effects, which will pass quickly in any case. However, if you have heart difficulties, discuss these with your doctor.
   
• Develop a crisis plan for how to handle an emergency. Get your allergist or GP to help. Have this written out for family and friends - put it on the bulletin board at home; carry one in your pocket. If a child is the person at risk, make sure his teachers and friends' parents have a copy - along with the adrenaline. Make sure everyone knows where the adrenaline is when you go out, or when you are at home.
   
• Wear a Medic Alert talisman (details: 020 7833 3034).
   
• Be open about your allergy problem with your family, friends and colleagues. It's easy to avoid a Thai, Chinese or Indian restaurant if everyone knows you are allergic to peanuts.

The treatment for a serious allergic reaction is adrenaline (also known as epinephrine). During anaphylaxis, blood vessels leak, bronchial tissues swell and blood pressure drops, causing choking and collapse. Adrenaline (epinephrine) acts quickly to constrict blood vessels, relax smooth muscles in the lungs to improve breathing, stimulate the heartbeat and help to stop swelling around the face and lips (angioedema).
Pre-loaded adrenaline injection kits are available on prescription for those believed to be at risk. These are available in two strengths - adult and junior. The injection must be given, as directed, as soon as a serious reaction is suspected and an ambulance must be called. If there is no improvement in 5-10 minutes, give a second injection.

Because this must be administered without delay, patients known to be at risk often carry their own adrenaline injection kits for use in an emergency.

The injection many doctors prescribe is the EpiPen, an easy-to-use device with a concealed needle. The EpiPen is available on prescription and distributed by ALK -Abelló, 2 Tealgate, Hungerford, Berkshire RG17 0YT. Tel 01488 686016 or you can now buy online through their website at www.epipen.co.uk

A relatively new adrenaline injection kit called the Anapen is also available on prescription. It is manufactured and distributed by Celltech Pharmaceuticals Ltd, 208 Bath Road, Slough, Berkshire SL1 3WE. Tel 01753 447690.

Both companies provide trainer pens for practice purposes. For information on how to administer the EpiPen (click here) and Anapen, (click here).

It is important to emphasise that even after adrenaline is administered, medical assistance should be sought urgently because the effects may wear off after 5 to 10 minutes and the injection may have to be repeated.

In fact, doctors often prescribe more than one injection kit so that if medical assistance is delayed, patients may administer a second dose.

More than one child in 100 is believed to suffer severe allergic reactions to peanuts, tree nuts or both. A small but significant number are affected by other foods.