Why are you allergic?

Allergy is an abnormal response of the immune system to contact with a foreign substance called an allergen. Contact can be through the skin, the mucous membrane of any part of the respiratory tract, or the mucous membrane of the digestive tract. The allergic reaction, which can only develop after a first exposure, takes various forms, such as eczema, hay fever, allergic asthma or food allergy.

Causes

People with allergic reactions produce much more than the normal amount of the antibody immunoglobin (IgE). They also produce far more than the normal amounts of one particular granular cell, a mast cell.

IgE attaches to mast cells. When an allergen, such as a grain of pollen, combines with the IgE, the membrane of the mast cell becomes deformed. It ruptures, releasing some very irritating substances, especially histamine. These substances cause the allergy symptoms.

Infections are necessary

So-called helper T cells – a type of white blood cell – play an important role in the defense against infections. Th1 cells spring into action during an infection, delivering substances that attack and destroy unwanted invaders.

Th2 cells produce substances that are involved in the allergic response. Normally these two cells balance each other out, but if there are more Th2 cells, an allergic reaction can occur. Until birth, the Th2 cells predominate, because the baby in the womb is in fact a foreign body and is at risk of being rejected.

After infections, a baby learns to defend itself against bacteria and viruses with the help of Th1 cells, possibly reducing the chance of an allergy. In the absence of infections, the Th2 cells remain in control. You can then develop allergies.

More and more allergies

Due to improved hygiene and vaccinations, children suffer fewer infections. The number of allergies is rising markedly, especially in Western countries. For example, only 3 percent of Albanian children have asthma, compared to 22 to 40 percent of English children. In a ‘cleaner’ environment we come into contact with fewer bacteria and viruses, so that our body builds up less defenses.

Research shows that animals live 40 percent longer after exposure to small amounts of chemicals and radiation. So dirt isn’t all bad. For example, children who have regular contact with farm animals are less likely to develop an allergy.

Italian scientists found that soldiers with antibodies to the hepatitis A virus were less likely to have allergies than their peers without those antibodies. Hepatitis A is transmitted through feces, contaminated food and water. According to a British study, young children who bathe daily and wash their hands at least five times a day are more likely to develop an allergy than children who do not do so often.

Research at the National Jewish and Research Center in Denver of 1,680 newborns showed that babies are less prone to allergies the more dust their parental home contains.

A remedy for allergies

The best recipe for allergy is to avoid contact with the substance to which one is allergic. But that is not always easy and sometimes even impossible.

The first thing to do is to find out exactly which substance you are allergic to. Your doctor can provide you with prescription drugs, such as antihistamines. For itching, a cream or ointment is often prescribed. However, this does not address the cause of the ailment.

An increasingly used method is desensitization. The purpose of this is that a certain habituation occurs through careful contact with the allergen. A good method, but also a long way, which does not guarantee success. In case of a severe reaction that resembles an allergy or hypersensitivity, contact your doctor.