Sensitisation to Airborne Environmental Allergens: What Do We Know and What are the Problems?

The most widely distributed sources of allergens are the pyroglyphid Dermato phagoides pteronyssinus and Dermatophagoides farinae mites [1], temperate grass pollens [2] and cats [3]. Other important allergens with less global distributions are birch [4], olive [5], ragweed and mugwort pollens [6]. Cockroach allergy is important for inner-city dwellers in America [7]. Dog allergy has been more evident in regions with low exposure to other allergens but is also a frequent source of sensitisation elsewhere [8]. The glycyphagid mite Blomia tropicalis is important in highly populated tropical and subtropical regions [9]. The conifers Japanese cedar in Japan and mountain cedar in USA and to a lesser degree cypress are regionally important [10]. Allergens from Aspergillus, Alternaria, Cladosporium and Penicillium moulds sensitise 5–10% of most populations and are associated with severe asthma [11]. Emerging sources of sensitisation are domestic exposure to mice in inner city environments, and pollens from the weeds Salsola kali (Russian thistle or tumble weed) and Chenopodium album (lambs quarter or goosefoot) [5]. The pollens occur worldwide but have attracted interest in areas of desertification.