SENSITIZATION TO FORMALDEHYDE - RESULTS F ROM THE INFORMATION-NETWORK-OF-DEPARTMENTS-OF-DERMATOLOGY (IVDK) 1992 TO 1995

With the decreasing use of formaldehyde (e.g. in cosmetics), the forme rly frequently diagnosed sensitization to this hapten can be expected to become a less often encountered event. Therefore, surveillance of t he sensitization rates by clinical epidemiology may yield new results. Methods: 32.833 patients from 24 allergy departments were patch teste d with formaldehyde] 1% aq. Time of exposure to the patch test prepara tion was 48 h. in 19.120, and 24 h. in 13.713 patients. Only the 72 h reading was considered for further evaluation. In order to identify mo re distinctly the influence of individual factors taken from patient h istories, the cases with unequivocal allergic reaction (i.e. those wit h ++ and +++) were evaluated separately. Results: 699/32.833 (= 2.1%) were allergic to formaldehyde (24h exposure: 2.5%, 48h exposure: 1.9%) . 71.5% of the allergic reactions were rated as ''+''. The reaction in dex was 0.1, indicating a large number of doubtful and irritative reac tions. The sensitization rates did not change during the study period 1992 to 1995. The subgroup of patients with unequivocal (++ and +++) a llergic reactions (n = 199) differed from the controls with regard to several individual factors: the hands were more often (48% versus 31%) , the face less often (8% versus 15%) affected. An occupational cause was suspected more frequently (38% verus 16%). Health care and metal w orkers were overrepresented in the group sensitized to formaldehyde. C oncomitant reactions to other haptens: which can be used not only for the discussion of cross-reactions, but also as further information on possible exposure areas, were clearly more often found in the ''uneqiv ocal'' (++/+++) subgroup. Figures (reaction rates (%) in the study gro up and the control group) are presented separately for women (w) and m en (m): glutardialdehyde (w:28/4), (m:22/2), and glyoxal (w:22/<1), (m :11/<1), (both possibly cross reacting with formaldehyde, but the reac tion may also be related to a common exposure), quaternium 15 (w:26/<1 ), (m:17/<1), and diazolidinylurea (w:13/1), (m:8/<1), (both formaldeh yde releaser), isothiazolinones MI/MCI (w:18/2), (m:13/2) and chlorace tamide (w:5/1),(m:9/<1) (structurally unrelated, possibly related to a common exposure). Interestingly, the concomitant reactions to Methyld ibromoglutaronitril/phenoxyethanol (a preservative often used in cosme tics) were only slightly elevated in men (w:2/2), (m:7/2). From severa l concomitant reactions to allergens of the standard series, the follo wing would merit further discussion: fragrance mix (w:37/11), (m:22/9) , balm of perou (w: 19/7), (m: 12/6), colophony (w: 12/3), (m:9/3), th iuram-mix (w: 11/3), (m:8/2). The number of reactions to allergens wit h obviously no common exposure (e.g. neomycin or wool wax alcolhols) w as not enhanced. Comment: Sensitization rates to formaldehyde have dec reased in Germany as well as in other European countries during the la st two decades, but now bring stable on a level of 1 to 3%. This decre ase may not only be due to a decreased exposure to formaldehyde, but m ay be explained partly by a modified patch test procedure (e.g. testin g formaldehyde 1% instead of 2%). From the analysis of individual fact ors (frequent hand eczema, rare face dermatitis, occupational cause, c oncomitant reactions to other (industrial or occupational) biocides) o ne may conclude, that sensitization to formaldehyde is largely due to an occupational exposure. It can be expected. that cosmetics will no l onger play a role as primary sensitizers, and rarely as elicitors.