Neurogenic inflammation induced by capsaicin in patients with psoriasis.
Glinski W, Glinska-Ferenz M, Pierozynska-Dubowska M
Increasing doses of capsaicin were applied topically to the forearm skin of 30 patients with psoriasis, 16 patients with systemic scleroderma and 16 healthy volunteers. Only one-third of the patients with psoriasis responded with neurogenic inflammation to capsaicin doses of 0.125 and 0.25 microgram/cm2 in contrast to 81% of scleroderma patients and all the normal controls, who showed a positive cutaneous reaction. Higher doses of capsaicin (0.5-4 micrograms/cm2) were required to induce erythema and flare in patients with late-onset psoriasis (after 21 years of age) as well as in patients with more than 40% of skin surface involved with psoriatic lesion.