Exacerbation of pustulosis palmaris et plantaris after topical application of metals accompanied by elevated levels of leukotriene B4 in pustules

Background: Pustulosis palmaris et plantaris (PPP) is a chronic inflammatory disease consisting of polymorphonuclear leukocyte infiltration, and is often exacerbated by focal infections such as tonsillitis. In some cases, metal allergy has been reported. Objective: The purpose of this study was to evaluate (1) the significance of metal allergy in the formation of pustules, and (2) the participation of leukotriene (LT) B-4 in the formation of pustules of PPP. Methods: Patch tests with metals were performed on 7 patients with PPP, and both pustular and plasma levels of LTB4 were measured in these 7 patients before and 48 hours after metal patch tests. Results: Palmoplantar pustules were exacerbated after the metal patch tests in all 7 patients. The mean levels of LTB4 in plasma and pustules of the volar surface at 48 hours after the metal patch tests were significantly higher than those before the metal patch tests. Conclusion: Metals can be important in the pathogenesis of PPP by contributing to the induction of high LTB4 concentration in the pustules.