Temporal trends of preservative allergy in Denmark (1985-2008).
BACKGROUND
Most cosmetics and industrial products contain preservatives. Preservative allergy is common and, historically, changing contact allergy epidemics caused by preservatives have been observed. In 1997, Alan Dillarstone predicted a stable development of preservative allergy following mandatory ingredient labelling on cosmetic products.


OBJECTIVE
To investigate the development in the prevalence of preservative allergy in Denmark over a 24-year period (1985-2008) and to challenge the prediction made by Dillarstone.


METHODS
A retrospective analysis of patch test data was performed (n = 18179). Comparisons were made using a chi(2) test. Logistic regression analyses were used to test for associations.


RESULTS
The development of preservative allergy mirrored those of other European patch test centres. The development was not dependent on sex or age group. The prevalence was higher among women and those aged 41-60 years. Formaldehyde allergy was persistently prevalent over the study years. The overall prevalence of preservative allergy increased significantly (P(trend) = 0.001), mainly because of patch testing with additional preservatives in recent years.


CONCLUSIONS
Dillarstone's prediction was confirmed as the prevalence of contact allergy to individual preservatives remained relatively stable. However, the overall burden of preservative allergy seemed to increase. Introduction of new preservatives may add to the burden of contact allergy.
Department of Dermato-Allergology, National Allergy Research Centre, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark. jacpth01@geh.regionh.dk
Jacob P
JP
Thyssen
Kåre
K
Engkilde
Michael D
MD
Lundov
Berit C
BC
Carlsen
Torkil
T
Menné
Jeanne D
JD
Johansen
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002219:Carbamates / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D003257:Consumer Product Safety; D003358:Cosmetics / Q000009:adverse effects*; D003718:Denmark / Q000453:epidemiology; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology*; D009783:Dermatitis, Occupational / Q000453:epidemiology*; D005260:Female; D005557:Formaldehyde / Q000009:adverse effects; D006801:Humans; D006827:Hydantoins / Q000009:adverse effects; D008297:Male; D008709:Methenamine / Q000009:adverse effects / Q000031:analogs & derivatives; D008875:Middle Aged; D009570:Nitriles / Q000009:adverse effects; D010226:Parabens / Q000009:adverse effects; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D012189:Retrospective Studies; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives; D055815:Young Adult
D002219:Carbamates; D003358:Cosmetics; D006827:Hydantoins; D009570:Nitriles; D010226:Parabens; D011310:Preservatives, Pharmaceutical; D005557:Formaldehyde; C106572:3-iodo-2-propynylbutylcarbamate; D014508:Urea; C056057:1,3-dimethylol-5,5-dimethylhydantoin; C018375:quaternium-15; C044982:diazolidinylurea; D008709:Methenamine; C006048:imidazolidinyl urea; C039411:1,2-dibromo-2,4-dicyanobutane