Exposure to road traffic enhances allergic skin wheal responses and increases plasma neuropeptides and neurotrophins in patients with atopic eczema/dermatitis syndrome.

The effect of exposure to road traffic was studied by sitting on chairs for 30 min beside a road with heavy wheeled traffic. Exposure to road traffic enhanced allergen-induced, but not histamine-induced, skin wheal responses in 26 patients with atopic eczema/dermatitis syndrome, while it had no effect on skin wheal responses in 26 normal subjects. Exposure to road traffic also increased plasma levels of substance P, vasoactive intestinal peptide, nerve growth factor, and neurotrophin-3 in patients with atopic eczema/dermatitis syndrome, while it had no effect on these plasma parameters in normal subjects. Collectively, exposure to road traffic may aggravate allergic diseases by enhancing allergic responses with concomitant increase in plasma levels of neuropeptides and neurotrophins.