Recent Trends in Relationship Between Pustulosis Palmoplantaris and Metal Allergy

Objectives: Allergy to Dental alloy is widely recognized as a cause of various skin and oral mucosa diseases. Especially, Pustulosis Palmoplantaris(PPP) is well known. Since 1998, clinical diagnosis of allergy to dental alloy have been done at the Dental Allergy Clinic of Tokyo Medical and Dental University. The objective of this study was to show the recent relationship between PPP and dental metal allergy within a retrospective study.
Methods: 2,123 outpatients from 2006 to 2013 were investigated by Patch testing according to the protocol recommended by the International Contact Dermatitis Research Group. The testers were removed after 48 hours. Skin readings were performed at 48 hours, 72 hours and 1 week. We analyzed the date by using the chi-squared test at a confidence level of 95%.
Results: 269 of 2,123 outpatients (12.7%) were diagnosed as PPP. There was no significant difference in the sex ratio between PPP outpatients and except PPP outpatients. (p>0.05). The number of over 70 years old patients among PPP outpatients was significantly less than that among except PPP outpatients (p<0.05).
Conclusions: In recent 8 years study, the positive rate of Palladium(Pd) slightly increased. The Positive rate of Mercury(Hg), however, goes down for approximately 3%. Nickel(Ni) was still the most frequent allergen among PPP outpatients.