The term allergy refers to a immune mediated hypersensitivity. This simply means that when your body is exposed to certain substances (allergens), the immune system misinterprets this substance as a foreign invader. This causes the immune system to overreact and attack the body’s tissues.

What is an immune hypersensitivity?

The immune system carefully coordinates its activity to protect the body and reduce the impact of injury by the process known as inflammation. It is made up of cells and chemicals, each of which play an important role in orchestrating an appropriate response to an attack from a microogranism like a virus or bacteria. One of the ways the immune system works is to produce specific chemicals known as antibodies. This allows the immune cells to identify the invaders and initiate the attack.

In a person who is allergic, the immune system becomes hypersensitive. In this state, it misinterprets signals and triggers an immune response when there is no foreign invader. Antibodies known as immunoglobulin-E (IgE) are usually responsible for the incorrect immune response in a person who is allergic. It triggers the immune cells to begin their attack and cause inflammation. This tends to occur more in certain areas like the lining of the nose, air passages and skin.

Since the body responds to allergens, rather than invaders, this process is known as immune mediate hypersensitivity. It means that the immune system is too sensitive and reacts inappropriately.

What are allergens?

Allergens are those compounds that trigger the immune mediated reaction. They are not invaders like bacteria and viruses. Allergens can be divided into inhaled (airborne) and ingested (food) allergens.

Any compound has the potential to be an allergen but common allergens include :

Ingested Allergens

• Milk and dairy products
• Egg yolk
• Wheat
• Nuts
• Soy
• Certain drugs

Inhaled Allergens

• Pollen
• Insect bites
• Animal hair (dander)
• Moulds
• Cockroaches
• Dust mites

What are common allergic conditions?

The most common allergic conditions are asthma, hay fever and eczema. These three conditions are known as the allergic triad and are due to an immune mediate hypersensitivity. A predisposition to an allergy is inherited although allergies to individual allergens may differ from person to person within the same family. Allergies tend to develop early in life and are more common in babies who are not breastfed.

Allergies may start later in life but are usually not as persistent as allergies that develop in childhood.

What is the treatment for allergies?

Treatment usually consists of antihistamines. These drugs prevent the immune cells from releasing histamine, a chemical that causes inflammation and further increases the immune response. In severe allergic conditions, you may have to use corticosteroids to prevent acute attacks and reduce the severity of the condition.