The mechanism by which topical sodium cromoglicate relieves allergen and histamine-induced skin inflammation was assessed in 60 subjects, 20 of whom were allergic to specific allergens. Sodium cromoglicate aqueous cream 0.2, 1 or 4% or placebo were applied in a randomized, single-blind manner to four areas on each forearm (two sites/arm) and covered with an occlusive dressing. Skin prick tests were conducted 1 h later with specific allergens in the allergic subjects and with codeine (9 mg/mL; n = 20) or histamine (10 mg/mL; n = 20) in the nonallergic subjects. Wheal volume, dermal temperature increase, erythema and pruritus intensity were measured at 0, 5, 10 and 15 min. Sodium cromoglicate ...