Cutaneous Resorption of Lead After External Use of Lead-Containing Ointments in Volunteers with Healthy Skin

Abstract

Lead-containing ointments are frequently used in anthroposophic medicine. In a prospective, open-label phase 1 study, 33 volunteers at the Ambulatory Clinic for Complementary and Alternative Medicine at the Free University of Berlin, aged 18-65 years, were exposed to 100 g Plumbum metallicum 0.4% ointment (Weleda, Germany) over a 4-week period. The lead-containing ointment was regularly applied to the cubital side of the forearm. Regular measurements of lead concentrations in whole blood, urine, and scalp hair were determined. None of the 33 volunteers showed an increase in lead concentrations in the 3 investigated compartments after 4 and 8 weeks. Blood lead levels (average value) decreased significantly from baseline to the first week (P < 0.05). Average values in the following investigations (weeks 3, 4, and 8) were significantly lower than at baseline (P < 0.05). There was no increase in lead levels in the scalp hair after 8 weeks (P < 0.05). The results show that the commonly prescribed lead-containing ointment Plumbum metallicum 0.4% in humans with an intact skin does not present a toxic risk.