Introduction Allergy affects more than 20% of the populations of most developed countries. The major allergic diseases, allergic rhinitis, asthma, food allergies and urticaria, are chronic, cause major disability, and are costly both to the individual and to the society (World Allergy Organisation (WAO) white book 2013). Besides occupational allergies, the most common allergies are caused by food, pollen, dust, mold, animal dander, insect sting, medications…Allergic phenomena are due to an exacerbated response of the immune system to antigens that are tolerated by non-allergic patients.