What is an allergy?
An allergy is an excessive defence reaction of the immune system to an environmental substance that is harmless per se. The immune system cannot distinguish between “dangerous” and “harmless” with the allergens.
In principle, any environmental substance can be an allergen. Inhaling these substances (inhalation allergy or aeroallergen) can result in a respiratory allergy. However, merely touching certain substances (contact allergens) can also lead to allergic reactions in some cases.
|Allergic rhinitis and/or conjunctivitis||Pollen, dust mites, mould, pet hair||Watery discharge from the nose, congestion, sneezing fits, itchy nose and/or throat|
Dust mites, pollen, pet hair, mould
|Respiratory complaints with tightness in the chest, dry cough, wheezing, shortness of breath|
|Atopic dermatitis||Metals, cosmetics, preservatives||Dry skin, swelling, persistent itching|
|Food allergy||Shrimp, strawberries, eggs, milk, nuts||Gastrointestinal disorders or diarrhoea, persistent itching|
|Insecticide allergy, drug allergy||Bee poison, wasp poison, penicillin drugs||Skin reactions, angioedema|
The causes for this malfunction of the immune system include inherited genetic predispositions along with certain environmental factors during childhood and later years of life. Several recent studies have shown that there is a link between air pollution and the occurrence of respiratory ailments and asthma.*
* Patel MM. et al.: Air pollution and childhood asthma: recent advances and future directions. Current Opinion in Pediatrics 2009; 21:235-242.