People these days increasingly complain of suffering from allergies - to pollen, to cats, to dust, to certain foods like peanuts or shellfish, for example. But what exactly are allergies and why do we develop them! Well, an allergy is the body reacting to something that is trying to harm it. Sometimes the reaction is mild - sneezing or a rash, perhaps - but in extreme cases it can be life-threatening. In an allergic reaction the body is stimulated to produce histamines, which help to get rid of what is harmful. So, your eyes and nose may stream as a way of losing irritating particles or your skin may itch in order to make you scratch it and so remove any harmful parasites. In some societies these days, allergic reactions occur without the person being in a harmful situation. However, in situations where, say, hygiene is less developed, then the body's immune system spends its early years fighting off genuine problems and so does not tend to over-react to harmless irritants at a later stage. So, how to deal with an allergy? The first step has to be to ascertain what triggers the allergic reaction and then to avoid contact with that allergen as far as is possible. If avoidance is impossible, anti-histamines can be prescribed to minimise the symptoms experienced by the sufferer.