The prevalence of chromium allergy in Denmark is currently increasing as a result of leather exposure.
BACKGROUND
Chromium allergy has traditionally been caused by occupational skin contact with cement. In 1983, Danish legislation made the addition of ferrous sulphate compulsory in cement to reduce the water-soluble chromium content to not more than 2 ppm. An effect from this intervention has previously been demonstrated among Danish construction workers.


OBJECTIVE
To investigate the development of chromium allergy among patients with dermatitis tested between 1985 and 2007 in Denmark. Furthermore, to determine causative exposures in patients with chromium allergy.


METHODS
A retrospective analysis of patch test data was performed (n = 16,228) and charts from patients with chromium allergy were reviewed. Comparisons were made using a chi(2) test. Logistic regression analyses were used to test for associations.


RESULTS
The prevalence of chromium allergy decreased significantly from 3.6% in 1985 to 1% in 1995 (P(trend) < 0.001) but increased to 3.3% in 2007 (P(trend) < 0.001). The frequency of clinically relevant cement exposure decreased significantly among patients with chromium allergy from 12.7% in 1989-1994 to 3.0% (P < 0.01) in 1995-2007, whereas the frequency of relevant leather exposure increased significantly from 24.1% during 1989-1994 to 45.5% during 1995-2007 (P < 0.02).


CONCLUSIONS
Chromium allergy is currently increasing in Denmark due to leather exposure.
Thyssen
J P
JP
Department of Dermato-Allergology, National Allergy Research Centre, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark. jacpth01@geh.regionh.dk
Jensen
P
P
Carlsen
B C
BC
Engkilde
K
K
Menné
T
T
Johansen
J D
JD
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002857:Chromium / Q000633:toxicity*; D003020:Clothing / Q000009:adverse effects; D004396:Coloring Agents / Q000633:toxicity*; D003718:Denmark / Q000453:epidemiology; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology*; D005260:Female; D006229:Hand Dermatoses / Q000139:chemically induced / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010328:Patch Tests; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D013633:Tanning; D055815:Young Adult
D004396:Coloring Agents; D002857:Chromium