Proallergens of formaldehyde applied in patch testing of formaldehyde contact allergy.

The ability of the nonliquid, nonvolatile proallergen of formaldehyde, N-hydroxymethylsuccinimide, to test for contact allergy to formaldehyde has been investigated by in vitro penetration studies in human epidermis. Compared with the standard test, 1% formaldehyde in water, N-hydroxymethylsuccinimide equal to 0.8 mg formaldehyde gave a similar penetration profile. This is explained by cleavage of N-hydroxymethylsuccinimide into formaldehyde and carrier (succinimide) by transepidermal water on the surface of the skin. Results were confirmed by a guinea pig maximazation test on animals sensitized to formaldehyde and in a preliminary clinical study on nine patients with known allergy to formaldehyde.