An allergy is a reaction of the immune system to some substances which can be delivered into the body through various routes.
Some substances, like pollen or dander can be inhaled, while the others, like penicillin or insect venom can be injected. Even a slight touch, like a contact with latex in surgical gloves, may trigger an allergy. It can be ingested through food, especially milk, eggs, tree nuts, peanuts, shellfish, fin fish, wheat and soy.
Allergies become more and more widespread due to various reasons.
The most meaningful risk factor responsible for developing allergy is being a child of
a mother or father who are victims of allergy.
However, there has been a significant rise in the number of people having allergies within one generation and, as it is stated that any changes in the genetic make-up of a population require many generations to occur, other factors have to be involved.
Infant feeding is one of these factors. When infants are exposed to food allergens (mainly cows’ milk and eggs) earlier in life — they are more prone to develop allergic disease.
However, breast feeding does not totally protect the child because allergens from foods consumed by child’s mother can be secreted in her milk.
According to the studies, solid food should not be given to children before the age of four months; however, many children are given solids earlier. In the West, the child’s diet contains large quantities of commercially prepared foods. Such foods are full of preservatives and other chemicals. At the same time, the diet contains minor amount of vegetables and fresh fruit that are sources of protective antioxidants.
Antioxidants are chemicals that reduce the rate of breakdown of another chemical by oxidation. If the introduction of solid food to babies is delayed, it may protect babies against allergies, particularly eczema. The occurrence of eczema by the age of two is related straightforward with the number of different solid foods consumed by the baby before the age of four months. If a mother who feeds her baby with breast milk eliminates allergenic foods
(milk, eggs, fish and peanuts), an extra defensive effect is noticed.
Children who are exposed to high levels of air-borne allergens in the early life are at higher risk of developing allergic disease. Children born in spring when the pollen count is high are more prone to suffer from allergy to plant pollens at the age of ten than children born in other season.
Similarly, children exposed to pet allergens in first years of life are at increased risk of allergy. Although being sensitive to allergens may occur at every age, the first year of life is especially important, and there is evidence that exposures in mid and late pregnancy are also important.
Exposure to tobacco smoke after birth and even earlier (via the bloodstream of the mother) is clearly related to the development of allergies and allergic diseases like asthma. Such an exposure after birth increases the risk; children who live in smoking environment are twice as prone to be admitted to hospital because of chest illness as children who live in non-smoking households.
These children also experience significant reduction in lung functioning by the age of seven. Exposure to tobacco smoke is the most meaningful risk factor for the increase of allergic diseases, so it is truly alarming to see that smoking becomes more and more popular among women of childbearing age.
In Europe, children spend on average 90% of their time indoors so this environment is of higher importance than outdoor environmental factors. Contemporary buildings are made to be insulated, their levels of ventilation are poor, and these are risk factors for the development of allergies.
This may result from increased levels of chemical fumes from certain materials, such as plastics and synthetic paints, high humidity causing indoor mould growth and high levels of house-dust mite allergen. Such living conditions seem to have a very strong effect in children who are already at the risk due to a family history of asthma.
There is clear evidence that recurring viral and bacterial infections in early life may protect from the atopy and allergic diseases. Such infections support the production
of interferon-gamma. This chemical is found in higher levels in non-allergic people than in people who experience allergies.
If a child develops lower level of interferon-gamma due to the protection he or she gets from minor infections in early life, the chance of an allergy may be increasing inadvertently.
An excessive consumption of antibiotics causes similar effect. In contrast, children who have lots of older siblings, and who attend daycare centres where they contact with many other kids and their germs, are less prone to suffer from asthma and hay fever.
Western lifestyle, which means exposure to tobacco smoke, increased levels of animal and plant allergens, house-dust mite, living in humid and inappropriately ventilated houses, smaller families and delayed use of care centres for children, in combo with the Western diet with formula milk and the earlier introduction of solid foods - all act to increase the number of victims of allergic diseases.
