Urea, reaction products with formaldehyde and glyoxal

Endpoint summary

Description of key information

Reports on skin sensitisation in humans do not allow to specify DMDHEU as the cause of contact eczema in patients with contact to resin treated textiles.

Additional information

There are several reports available concerning skin sensitisation of the test substance in humans (Malten, 1964; Andersen & Harman, 1982; Tegner, 1985; Fregert & Tegner, 1971; Scheman et al., 1998). These reports have been evaluated as follows in course of the OECD SIDS program (2002):

 

“Thirty-seven substances which may be used in finishing textiles, including this test substance, namely DMDHEU, were patch-tested in 66 patients, who, anamnestically and/or clinically, were suspected of suffering from a textile finish contact eczema . In 27 patients positive patch-test reactions to various textile finishes and additives were observed after 48-h contact. 8 out of 24 patients tested for DMDHEU have a positive response to DMDHEU (50% in aq .). 6 out of these 8 patients showed also a positive response to formaldehyde (5 % in aq.) (Malten, 1964).

Among 428 eczema patients patch-tested with textile finish resins from 1970 to 1980 15 had allergic textile dermatitis based on history, clinical features and patch test results . DMDHEU (10 % in petrolatum) induced a positive reaction only in three out of ten patients tested who also react to formaldehyde (2% in aq .). A test performed with the patch-test material revealed free formaldehyde in all samples (amount not specified) (Andersen and Harman, 1982).

25 patients with dermatitis suspected to be caused by permanently-pressed colored sheets were subject to further clinical investigations. One out of six patch-tested patients reacted to DMDHEU, none reacted to formaldehyde. Patch-test concentrations and further details were not given (Tegner, 1985).

Fregert and Tegner (1971) reported a case of dermatitis from non-iron sheets and pillow cases. The patch-test was positive to DMDHEU but negative to other textile finishing resins and to formaldehyde. Patch-test concentrations and further details were not given. 10 out of 12 patients with positive patch-test reactions to older formaldehyde resins were patchtested with formaldehyde (1 % in aq.) and DMDHEU (4.5 % in aq.). All ten subjects reacted to formaldehyde and DMDHEU. Whereas the formaldehyde content on the finished textile was measured, no analysis of formaldehyde content in DMDHEU used for patch testing was performed (Remark: According to the producer up to 1% of free formaldehyde is contained in DMDHEU. As a consequence of dilution additional formaldehyde is formed due to hydrolysis) . In the 1960's use of DMDHEU yielded fabrics with approximately 500 ppm free formaldehyde . Fabrics treated with the latest modified DMDHEU resins predictably contain less than 75 ppm free formaldehyde. Most clothing today yields free formaldehyde levels unlikely to cause contact allergy in formaldehydeallergic individuals (Scheman et al ., 1998).

 

The above mentioned papers do not allow to specify DMDHEU as the cause of contact eczema in patients with contact to resin treated textiles. Most cases showed positive patch-test reactions to formaldehyde and DMDHEU. Even in few cases reacting only with DMDHEU it has to be considered that textile finishing resins on the basis of DMDHEU may contain up to 1% free formaldehyde. In none of the papers an analysis of the DMDHEU used for patch-testing was presented. Regarding a patch test concentration for DMDHEU of 5% and a free formaldehyde content of maximum 1% in DMDHEU 500 ppm formaldehyde in the test substance can be calculated; due to hydrolysis the actual formaldehyde concentration is higher. On the basis of the above reported cases the incidence of contact dermatitis from DMDHEU finished textile is regarded to be very low, especially compared to the wide spread use. According to EU regulations (EU, 1996) products containing formaldehyde in concentration of > 0.2 % have to be classified as skin sensitizer (R43).”