Background. Sensitization to nickel, cobalt and chromium is frequent in patch test
populations. The prevalence is affected by geographical and socio-cultural factors.
Objectives. To investigate the temporal trend of nickel, cobalt and chromium contact
sensitization between 1996 and 2010 in north-eastern Italy.
Patients/methods. Nineteen thousand and eighty-eight patients (67.2% women and
32.8%men)withsuspectedallergic dermatitisunderwentpatchtestingwith theEuropean
baseline series. The associations between nickel, cobalt and chromium sensitization and
patient age (in quintiles) and year of patch testing were investigated by means of
multivariate logistic regression analysis.
Results. The prevalence of nickel sensitization decreased significantly among younger
women (≤26 years), from 38.3% (1996–1998) to 31.9% (2002–2004), 28.3%
(2005–2007) and 29.0% (2008–2010), whereas an increase was observed in
the 36–45-year and 46–58-year age groups. The overall prevalence of chromium
sensitization dropped from 10.2% (1996–1998) to 4.6% (2008–2010) among women,
and from 11.3% (1996–1998) to 5.9% (2008–2010) among men. The prevalence of
cobalt sensitization increasedamongyoungermen(≤26 years), from2.7%(1996–1998)
to 7.3% (1999–2001), 9.6% (2002–2004), and 6.6% (2005–2007).
Conclusions. Our study showed a decreasing trend of nickel sensitization (only among
younger women) and of chromium sensitization in both sexes.
