An allergy is an immune reaction to some substance. In a person with allergies, the body’s immune system overreacts when it comes into contact with certain substances. These stimuli are known as allergens and trigger a range of signs and symptoms that we refer to as an allergic reaction. Allergies are not caused by the allergen – it is only triggered by the allergen.
Some common allergic conditions include asthma, eczema, hay fever and hives (urticaria).
Immune System Reaction
The immune system is designed to protect us. When any foreign organisms try to invade our body, the immune system ‘calls up’ its cells and chemicals to identify the invader and act against it. This entire process is carefully orchestrated to ensure that the immune system responds quickly and effectively.
In some people, this immune system reaction becomes a bit disordered. The immune system incorrectly identifies certain airborne substances, food and drink as an invader. It then initiates its immune response. Since there is no invading organism, the immune cells and chemicals start acting on the body’s tissues thereby causing inflammation, particularly the skin and mucus membranes of the eyes and air passages.
Causes and Symptoms of an Allergy
An allergic disposition may be inherited. Many children have allergies from early life, evident as asthma, eczema or hay fever. Individual allergies are not usually inherited but rather the tendency to be allergic is passed on from one generation to the next. Certain drugs and other unknown factors may also be the cause of an allergy. An allergen does not cause the allergy but it is the trigger for the allergic reaction.
Some common inhaled allergens which is present in the air include house dust mite, moulds, pollen, certain chemicals, dog hair and cat fur. Common ingested allergens which may be taken in food and drink include milk and dairy, wheat, soy, egg yolk and nuts. Certain preservatives, food additives and colourants may also be responsible, especially monosodium glutamate (MSG), sodium benzoate, sulphur dioxide and tartrazine.
The symptoms of an allergy varies depending on the area that it affects. Typically it produces itchy skin rashes, itchy eyes with redness and mucus discharge like a runny nose. Sneezing and wheezing may also be present especially in those with hay fever or asthma respectively.
Antihistamines are usually effective in controlling the severity of the allergic reaction. This will not totally stop the allergic reaction but reduces the allergy symptoms significantly. Corticosteroid drugs may also be used, especially in severe allergies or long term allergic conditions.