title: Suppression of immediate and late anti-IgE-induced skin reactions by topically applied alcohol/onion extract.
abstract: In a double blind study, alcohol/onion extract (5% ethanol) was injected simultaneously with 20 IU and 200 IU rabbit anti-human-IgE intradermally in 12 adult volunteers (6 atopics, 6 non-atopics). Diameters of wheals and flares were measured 10 min after and compared with control sites challenged with 20 IU and 200 IU anti-IgE in a 5% ethanol solution. The skin sites were then treated epidermally with 45% alcohol/onion extract and 45% ethanol under occlusion. Diameters of late cutaneous reactions were measured hourly. Oedema formation was clinically estimated according to an arbitrary scale and skin thickness measured with a calliper. In the onion-treated skin sites the wheal areas were significantly reduced (20 IU: control: 108 +/- 53 mm2; onion 69 +/- 42 mm2, P less than 0.05; 200 IU anti-IgE: control: 152 +/- 25 mm2, onion: 138 +/- 26 mm2, P less than 0.02). The oedema formation during the late phase skin reaction was markedly depressed (P less than 0.005 at 2 h, P less than 0.01 at 4 and 6 h, P less than 0.02 at 8 h). The extent of late skin reactions was slightly, but not significantly reduced. Obviously, onions contain pharmacologically active substances with anti-inflammatory and/or allergic properties.
mesh_terms: D000707:Anaphylaxis / Q000276:immunology; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology; D010936:Plant Extracts / Q000008:administration & dosage / Q000276:immunology*; D012882:Skin Tests; D013997:Time Factors
chemical_list: D000888:Antibodies, Anti-Idiotypic; D010936:Plant Extracts; D007073:Immunoglobulin E