Evidence suggests that allergic respiratory diseases such as rhinitis and bronchial asthma have become more common over the last few decades. Why this is so, has yet to be established. Among the factors implicated in this ''epidemic'' there are the followings:

• Better diagnosis: more patients with positivity to allergological tests
• Modern lifestyle: increased exposure to household irritants
• Reduced incidence of infections with a switch of T cells from Th1 to Th2
• Increased mobility with consequent exposure to new allergens
• Increased indoor and outdoor airborne pollutants.

Allergic respiratory diseases are known to be genetically determined. Therefore, the dissection of the relative contribution of environmental and genetic factors will provide a deeper understanding of the pathophysiology underlying the trends in allergic diseases.

Drastic environmental modifications have been targeted as the mean culprit for the rise. However, to induce an atopic- allergic sensitization, the environmental factors act in this way

EAACI-2-Napoli