Formaldehyde-releasers: relationship to formaldehyde contact allergy. Part 2: Metalworking fluids and remainder

Harmful Effect of Indoor Formaldehyde on Atopic Dermatitis in Children: A Longitudinal Study

Purpose

Evidence supporting a link between indoor formaldehyde exposure and atopic dermatitis (AD) in humans is limited. The purpose of this longitudinal study was to investigate whether AD symptoms in children could be affected by indoor formaldehyde levels in ordinary households.

Methods

Fifty-five children with moderate-to-severe AD aged under 18 years were enrolled as a panel. They were followed up from February 2019 through February 2020. Indoor formaldehyde levels of patients' houses and their AD symptoms were repeatedly measured on a daily basis. The generalized linear mixed model was utilized for statistical analysis. Subdivision analysis was performed by stratifying patients by sex, body mass index, presence of parental allergy, and indoor environments including mold/dampness, temperature, and relative humidity (RH).

Results

A total of 4,789 person-days of AD symptom data were collected. The average concentration of formaldehyde was 13.6 ± 16.4 ppb, with the highest value found in spring (18.1 ± 20.6 ppb). Higher levels of formaldehyde were observed when there was parental smoking, increased indoor temperature over 25.5°C, or RH over 60% (P < 0.0001). When the effect size was compared between each season after controlling for ambient particulate matter, temperature, and RH, an increase in 10 ppb of formaldehyde increased AD symptoms by 79.2% (95% confidence interval [CI], 19.6–168.4) in spring and by 39.9% (95% CI, 14.3–71.2) in summer. AD symptoms in children aged 6−18 years appeared to increase significantly, whereas there was no significant increase in children under 6 years. When indoor temperature was over 25.5°C, an increase in formaldehyde by 10 ppb increased AD symptoms by 17.8% (95% CI, 3.9–33.6).

Conclusions

Indoor formaldehyde can exacerbate AD symptom in children with moderate-to-severe AD, particularly in spring and summer, even at allowable levels. Thus, minimizing exposure to indoor formaldehyde may be needed for the proper management of AD in children.

Single- and repeated-dose 28-day oral toxicity study of MDM hydantoin in Sprague-Dawley rats

1-(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione (MDM hydantoin) is a commonly used antiseptic preservative in cosmetics. However, limited toxicity information data are available for this chemical. The aim of this study was to obtain toxicity data for MDM hydantoin through single- and repeated-dose toxicity studies in Sprague-Dawley (SD) rats. In the single-dose toxicity study, MDM hydantoin was administered once orally to SD rats at four doses (5, 50, 300, and 2000 mg/kg/day). There was no significant difference in mortality, clinical signs, and body weight change for 14 days among the animals treated with the different doses in this study. Hence, the approximate lethal dose of MDM hydantoin was considered higher than 2000 mg/kg/day. Based on the results of the dose-range finding study, a 28-day repeated-dose oral toxicity study was conducted. MDM hydantoin was administered orally to SD rats at doses of 125, 250, 500, and 1000 mg/kg/day throughout an experimental period of 28 days. In the repeated-dose oral toxicity study, the adverse effects caused by MDM hydantoin were not detected in terms of body weight, clinical signs, food and water intake, hematology, organ weights, gross pathology, and histopathology. Therefore, the no-observed-adverse-effect level of MDM hydantoin was considered to be greater than 1000 mg/kg/day.

Undeclared formaldehyde levels in patient consumer products: formaldehyde test kit utility

PURPOSE

Formaldehyde allergic contact dermatitis (ACD) may be due to products with free formaldehyde or formaldehyde-releasing agents; however, assessment of formaldehyde levels in such products is infrequently conducted. The present study quantifies total releasable formaldehyde from "in-use" products associated with formaldehyde ACD and tests the utility of commercially available formaldehyde spot test kits.

MATERIALS AND METHODS

Personal care products from 2 patients with ACD to formaldehyde were initially screened at the clinic for formaldehyde using a formaldehyde spot test kit. Formaldehyde positive products were sent to the laboratory for confirmation by gas chromatography-mass spectrometry. In addition, 4 formaldehyde spot test kits were evaluated for potential utility in a clinical setting.

RESULTS

Nine of the 10 formaldehyde spot test kit positive products obtained from formaldehyde allergic patients had formaldehyde with total releasable formaldehyde levels ranging from 5.4 to 269.4 µg/g. Of these, only two shampoos tested listed a formaldehyde-releasing agent in the ingredients or product literature. Subsequently, commercially available formaldehyde spot test kits were evaluated in the laboratory for ability to identify formaldehyde in personal care products.

CONCLUSIONS

Chemical based formaldehyde spot test were more reliable than the enzymatic based test in identifying product releasable formaldehyde content. It is concluded that product labeled ingredient lists and available information are often inadequate to confirm the potential for formaldehyde exposure and chemical based spot test kits may have utility for identification of potential formaldehyde exposure from personal care products.