Allergies are on the increase across the world and it is estimated that as many as one in three people will suffer from an allergy at some point in their lives[1].

An allergy is where the body has an adverse reaction to a usually harmless substance (allergen) such as pollen, chemicals, drugs, food or pets. When the body’s immune system recognises the allergen as foreign and therefore harmful, it produces a type of antibody called immunoglobulin E (IgE), which recognises and attacks the invading allergen. This attack in turn triggers the release of chemicals in the body called histamine and leukotrienes. It is these chemicals which cause the allergic symptoms such as sneezing and watery eyes[2].

Symptoms

The symptoms of an allergic reaction will vary from person to person and depend on what the patient is allergic to.

Reactions can include a skin rash or hives, itchy, watery eyes, sneezing and some nasal congestion. Sometimes allergic symptoms such as a rash or wheezing can be troublesome enough to affect daily activities or disrupt sleep.

In its severest form, an allergic reaction can be life threatening. Anaphylactic shock is a type of allergic reaction that comes on suddenly and affects the whole body. Symptoms may include difficulty swallowing or breathing, abdominal pain, cramps, vomiting, diarrhoea, hives and swelling of the mouth or throat. Mental confusion and dizziness can also occur because of a sudden drop in blood pressure.

<PRACTICE POINT>

Many allergy symptoms are similar to those of cold or flu. Think how you would decide whether a patient is suffering from an allergy or a cold. Discuss your answers with your pharmacist.