Reduction of nickel-induced contact hypersensitivity reactions by topical tea tree oil in humans.

Title	Reduction of nickel-induced contact hypersensitivity reactions by topical tea tree oil in humans.
Authors	T. J. Jones, Ronald Hart, David A. Pearce
Magazine	Inflammation Research
Date	12/31/2004
DOI	10.1007/s00011-004-1317-6
Introduction	Tea tree oil (TTO) is known for its antimicrobial properties, but its anti-inflammatory effects on human skin are anecdotal and require evaluation. This study assesses TTO's impact on nickel-induced contact hypersensitivity in human dorsal skin. TTO (100%), a 5% TTO lotion, a placebo lotion, or 100% macadamia oil were applied after nickel exposure. Flare area and erythema index were measured. TTO (100%) significantly reduced flare area and erythema index compared to nickel-only sites, particularly in nickel-sensitive subjects with prolonged hypersensitivity response. The 5% TTO lotion, placebo lotion, and macadamia oil demonstrated no significant effects. TTO inhibited nickel-induced proliferation in peripheral blood mononuclear cells from nickel-sensitive subjects. Topical 100% TTO may benefit nickel-induced hypersensitivity. Further research is necessary on its mechanism, possibly affecting antigen-presenting cells or processes in nickel-induced hypersensitivity and related vascular changes.
Quote	T. J. Jones, Ronald P. Hart and David A. Pearce. Reduction of nickel-induced contact hypersensitivity reactions by topical tea tree oil in humans. 2004. DOI: 10.1007/s00011-004-1317-6
Element	Nickel (Ni)
Materials	Biomaterials
Industry	Pharmaceuticals & Cosmetics