Contact allergy to and allergic contact dermatitis from formaldehyde and formaldehyde releasers: A clinical review and update

Abstract

This review aims to provide a clinically useful update regarding the role of formaldehyde (FA) and its five main releasers (FRs) quaternium‐15, diazolidinyl urea, DMDM hydantoin, imidazolidinyl urea, and 2‐bromo‐2‐nitropropane‐1,3‐diol (bronopol) in contact allergy and allergic contact dermatitis. These ubiquitous preservatives are still often present, and sometimes undeclared, in cosmetics, pharmaceuticals, medical devices, household detergents, and chemical (industrial) products. In Europe, the use of free FA and quaternium‐15 in cosmetics is forbidden and contact allergy rates have been found to be stable to decreasing. However, FA/FRs still readily provoke localized (eg, facial/hand), airborne, and generalized dermatitis, and may also complicate atopic and stasis dermatitis, or result in nummular dermatitis. Seborrheic‐, rosacea‐ and impetigo‐like dermatitis have recently been reported. For a correct diagnosis, FA 2% aq. (0.60 mg/cm2) should be used, and particularly the FRs bronopol 0.5% pet. and diazolidinyl urea 2% pet. should be patch tested separately in a baseline series. If sensitization to FA occurs, both FA and FRs should preferably be avoided, except perhaps for bronopol in case it tests negatively. If a patient reacts to one or more FRs (such as bronopol or diazolidinyl/imidazolidinyl urea), but not to FA, then the specific FR(s) should be avoided.

Trends in formaldehyde and formaldehyde‐releaser contact allergies as compared with market exposure in Thailand

“…Positive patch test reactions to formaldehyde were more common in certain occupations, such as homemaker, tailor, and mechanic. 1,10 Regarding the FRs, significantly higher proportions of positive patch test reactions to imidazolidinyl urea were found for men (36.5% vs. 21.4%) and older age (49.8 vs. 41.8 years) than for those with negative reactions.…”

Occupational contact allergy: The European perspective–Analysis of patch test data from ESSCA between 2011 and 2020

“…Formaldehyde and formaldehyde releasers are still frequently used as preservatives in household detergents, cosmetic and pharmaceutical products and various industrial products. 63,64 Sensitization rates to formaldehyde (1% and 2% aq.) were lower in Europe (2.7% [95% CI 2.5%-3%] compared to the United States and Canada 3.9%).…”

The European baseline series and recommended additions: 2023

“…Of those recommended additions to the EBS in 2019. Formaldehyde releasing preservatives 13 : The test concentration of formaldehyde was increased to 2% aqua (aq.) from 2014 with a doubling in the detection rate of formaldehyde allergy 14 .…”