Are we born with allergies or do we acquire them? Is being allergic a permanent condition? Why are people only allergic to certain substances?
These were some of the questions we put to Dr. Pedro Morais Silva (Hospital de Alvor and Clínica Particular AlgarveShopping), a specialist in Immunoallergology and guest assistant at the Faculty of Medicine of the Algarve.
What is an allergy?
An allergy is an exaggerated and inadequate response of our immune system against inoffensive substances in the environment. In a normal situation, our organism fights agents that can cause diseases, such as bacteria or parasites and “tolerates” beneficial substances such as food, the air that we breathe or medications.
For allergy sufferers, they form special antibodies (of the IgE type) that incorrectly interpret an inoffensive substance (an allergen) as an aggressor. These antibodies live in the nose, eyes, bronchi, skin and digestive system and cause an intense inflammation that gives rise to the typical symptoms of the allergy.
Why do we become allergic?
A genetic, personal or family predisposition to produce these special antibodies against environmental allergens is referred to as “atopy”.
A child with an allergic parent, for example, has a 40%-60% risk of also getting an allergy. If both parents are allergic, the possibility increases to 60%-80%. On the other hand, the risk is quite low (about 5%) if there are no allergies in the family.
But allergic diseases involve multiple factors, which means that they are influenced as much by genetics as by environmental factors. Viral respiratory infections and exposure to pollutants, especially to tobacco smoke, appear to be equally important in the occurrence of allergy problems. Additionally, a sedentary lifestyle, obesity and infrequent contact with nature also appear to contribute towards the epidemic of allergies that sprung up at the end of the 20th Century.
Are allergies really increasing? Proportionally, are there more allergic children or adults?
There seem to be no doubts that allergic diseases are becoming more and more frequent, especially in children. It is estimated that in Portugal, approximately 10% of the population (about 1 million people) suffer from bronchial asthma. And in the paediatric age this percentage is even greater, about 15%. Besides this, more than 20% of Portuguese children suffer from rhinitis, 10% have atopic eczema and between 5%-10% suffer from food allergies. The prevalence of all of these diseases has practically doubled in the last 25 years.
Is it possible to prevent
allergies?
In regard to children, there are some attitudes that can make a big difference. Exclusively breastfeeding for the first 6 months of life for all newborns is recommended, for its nutritional value as well as for its capacity to correctly regulate the immune system. This measure seems to have a protective value in the development of several allergies, especially eczema, early childhood asthma and food allergies. When it is not possible to breastfeed, or when the breast milk is insufficient, the hypoallergenic formulas of hydrolysed milk seem to be superior to normal formulas or soy formulas in the prevention of allergies for children with allergic parents.
Finally, exposure to tobacco smoke (and less frequently to smoke from a fireplace) during gestation, for the newborn and in early childhood seems to be incredibly prejudicial for the pulmonary development of the child.
Even so, even when all possible care is given, allergies sometimes appear. Fortunately, Medicine has followed this progressive increase in allergy diseases and today there are diagnoses and treatment to minimise and even reverse the impact that these have on the quality of life of the allergy sufferers.