Cough sensitivity in atopic dermatitis.

The aim of study was to investigate the cough sensitivity (C2) to capsaicin (CAPS) in patients with atopic dermatitis without clinical respiratory symptoms. Cough sensitivity (C2) is defined as the lowest CAPS concentration, which evokes two or more coughs. Forty eight dermatological patients (21 M, 27 F; mean age 44 yr) and 24 healthy volunteers (14 M, 10 F; mean age 37 yr) inhaled deep breath (2 l) of CAPS aerosol in doubled concentrations (from 0.02 to 200 micromol/l) (Pari Provokationstest I, PARI WERK; mass median diameter 1.2 microm). Cough sensitivity (C2) expressed as geometric mean (95% CI) of CAPS concentration was 0.13 micromol/l (0.06-0.31) in 26 patients with atopic dermatitis (10 M, 16 F; mean age 41 yr), 5.51 micromol/l (1.33-22.90) in 22 patients with psoriasis (11 M, 11 F; mean age 46 yr) and 4.29 micromol/l (2.54-7.26) in 24 controls. There is significant difference of cough sensitivity (C2) between patients with atopic dermatitis and healthy volunteers (p<0.001) and also between patients with atopic dermatitis and psoriasis (p<0.001). Cough sensitivity (C2) in atopic dermatitis patients without clinical respiratory symptoms is significantly increased. In patients with psoriasis cough sensitivity (C2) is not significantly changed.