Longitudinal effects of avoidance of powdered NRL glove exposure on puncture skin test (PST) reactivity to non-ammoniated latex (NAL) and purified native allergens (Hev b) have not been assessed. Endpoint percutaneous threshold concentrations (EPCs) in 34 of 62 health care workers (HCWs; mean age = 45 yrs, range 26-73 yrs) first evaluated in 2000 were re-evaluated in 2005 by PST with NAL, native Hevs bl, b2, b3, b4, b6.01, b7.01 and b13 and recombinant Hev b5. A period of 56.2 + 2.2 months (mean + SD) elapsed between the two evaluations. Reduced NRL sensitization was defined on retesting as a conversion to a negative NAL PST or a 2-log increase in NAL EPC over the period 2000-2005. In 2005, 7/34 (21 %) of HCWs had lost all PST sensitivity to NAL and all Hev b proteins; 26/34 HCWs showed reduced NRL sensitization from 2000. Significant increases in median EPCs for NAL (Wilcoxon, p<0.001) and reductions in the proportions of HCWs with positive PSTs to Hevs b2, b5, b6.01, and b7.01 were observed over the period from 2000-2005 (McNemar's, p<0.05 to p<0.001). An association with reduced NRL sensitization was observed in those individuals who changed jobs to one without latex glove exposure (Phi coefficient, 0.652, p<0.002). Personal avoidance of exposure in NRL sensitized HCWs produces detectable long term reduction or loss of skin sensitivity to NAL and Hev b allergens.