Health Guide

Life Threatening Allergies

Introduction :
An allergy is excess sensitivity to a substance that produces a reaction in the body.


Types :
Hay fever, eczema, asthma, itchy eyes and hives may all be caused by an allergy.


Cause :
Allergies may occur on exposure to almost any type of chemical. Animal hair, dust, milk, eggs, pollen, fish, fruit, insect bites, moulds and parasites are just a few of the thousands of possible allergic substances. An allergen is a substance that causes an allergic reaction. When the body first encounters an allergen, the defence mechanisms of the body are triggered, but there is usually no detectable effect. On the second and subsequent occasions of exposure to the allergen, the defence mechanism over reacts, causing effects that may be merely a nuisance, or severe and life threatening, in different areas of the body. Pollens, dusts or chemicals may start the allergic reaction, causing the release of a substance (histamine) from special (mast) cells in the nose, skin, eyes etc. Histamine causes rapid swelling of the tissue, which may secretes copious amounts of watery fluid, and become intensely itchy.


Prevention :
Avoiding foods, chemicals, other substances and situations that are known to trigger the allergy. Antihistamines may be taken on a regular basis if avoidance is not possible.


Investigations :
Tests may be performed to determine whether or not you are allergic to a particular substance, but because there are so many possibilities, you must have some idea of what is causing the problem before the tests are commenced. The tests may take the form of skin pricks with a number of suspected substances, or blood tests that can detect the bodies reaction to an allergen.


Treatment :
The body gradually breaks down the histamine itself, and the reaction disappears, but this process can be speeded up by the use of anti-histamine drugs (see Medication Table) that are taken by mouth or injection to destroy the histamine that is causing the allergy reaction. In some cases, nasal or inhaled sprays (see Medication Table) can prevent the release of the histamine by the cells, and therefore prevent any allergic reaction, but these must be used all the time, as the problem will probably recur if they are ceased. If someone is found to be highly allergic to a specific substance, they can be desensitised so that they do not react as strongly, or sometimes do not react at all. This process is often long and involved, and unfortunately does not always work, but many people have had life threatening and disabling allergies cured or reduced by this procedure. Allergists, who are specially trained doctors, usually undertake allergy desensitisation. The patient has prepared an individualised mixture of the substance to which they are allergic. This mixture is extremely dilute, and the patient is gradually exposed to stronger and stronger concentrations until the body no longer responds to cause an allergic reaction. The desensitising mixture is usually given by a series of small injections at regular intervals over several months.


Diet :
Avoid any foods or drinks that are known to trigger an allergy reaction.


Complications :
Allergies in most people are annoying rather than serious, but in a small number of victims, they may be life threatening. Those who know of a life threatening allergy should always carry adrenaline with them, to be self-injected if they have an attack.


Outcome :
Allergies should not be severe enough to significantly alter your lifestyle if adequately treated by you and your doctor.


Further information:
Allergy Associations exist in several states. People with severe allergies should wear a bracelet or necklet carrying information about the allergy to warn doctors in an emergency. These are available through the Medic Alert Foundation.


Related conditions
Asthma, Conjunctivitis, Eczema, Hay fever.