Cough sensitivity in localized sclerodermia with no clinical symptoms from lower airways
Cough sensitivity is increased in patients with atopic dermatitis, although they have no clinical symptoms from the lower airways. In the present study we examined the cough sensitivity to capsaicin in patients, who had no clinical respiratory symptoms, with sclerodermia localized to the skin. Cough sensitivity was defined as the lowest capsaicin concentration, which evokes 2 or more coughs. Twelve patients and 12 healthy matched volunteers, as a comparison group, inhaled deep breaths (2 L) of a capsaicin aerosol in doubled concentrations (from 0.02 to 200 µmol/L). Cough sensitivity, expressed as a geometric mean (95% CI) of capsaicin concentration, was 0.15 µmol/L (0.04 to 0.56) in the patients with localized sclerodermia and 4.96 µmol/L (2.50 to 9.85) in controls, which made a significant difference towards higher cough sensitivity in sclerodemia, respiratory symptom-free patients. Thus, disease processes localized outside the respiratory tract may have surreptitious pulmonary manifestation that is brought to light by the capsaicin cough test.