Evidence map›Paper›PMID 42035787›Full record

SynthesisContact dermatitis2026

The Prevalence of Contact Allergy to Formaldehyde and Formaldehyde Releasers: A Systematic Review and Meta-Analysis.

Kian Karimian, Daniel Isufi, Mikkel Bak Jensen, Rebekka Søgaard, Jeanne Duus Johansen, Jakob Ferløv Baselius Schwensen

Abstract readSystematic ReviewMeta-Analysis
In one paragraph

Synthesis in Contact dermatitis, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Kian KarimianNational Allergy Research Centre, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Hellerup, Denmark.ORCID https://orcid.org/0009-0005-1580-4671
Daniel IsufiDepartment of Dermatology and Allergy, Herlev and Gentofte - Copenhagen University Hospital, Copenhagen, Denmark.ORCID https://orcid.org/0009-0003-2780-3604
Mikkel Bak JensenNational Allergy Research Centre, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Hellerup, Denmark.ORCID https://orcid.org/0000-0003-2442-5735
Rebekka SøgaardNational Allergy Research Centre, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Hellerup, Denmark.ORCID https://orcid.org/0009-0004-7749-0383
Jeanne Duus JohansenNational Allergy Research Centre, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Hellerup, Denmark.ORCID https://orcid.org/0000-0002-3537-8463
Jakob Ferløv Baselius SchwensenNational Allergy Research Centre, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Hellerup, Denmark.ORCID https://orcid.org/0009-0007-9756-656X

Funding

The Danish Environmental Protection Agency under the Ministry of Environment of Denmark
6 · The paper itself

Abstract

Formaldehyde and its releasers are common preservatives and potent sensitizers. This meta-analysis aimed to estimate the prevalence of formaldehyde contact allergy and allergy to its five most common releasers among dermatitis patients. Two authors independently searched PubMed, Embase, and Web of Science from inception to 30th September 2025. A proportion meta-analysis was conducted using a random-effects model. A total of 158 studies involving 1 347 638 dermatitis patients were included. The pooled prevalence of formaldehyde contact allergy was 2.88% (95% CI 2.55-3.24) with clinical relevance at 41.57%. The pooled prevalence for releasers was 2.76% for 2-bromo-2-nitropropane-1,3-diol, 1.89% for quaternium-15, 1.42% for diazolidinyl urea, 1.37% for DMDM hydantoin, and 1.20% for imidazolidinyl urea. Quaternium-15 showed the highest clinical relevance at 55.67%. Significant sensitization rates were observed in different geographic regions, with the highest prevalence found in North America (6.8%). The prevalence rate was 2.96% among children and 2.61% among adults, with no significant difference. The prevalence rate was 2.65% among patients with atopic dermatitis (AD) and 2.85% among patients without AD, with no significant difference. The profound geographic disparities suggest that regulatory interventions, such as the EU's prohibition of formaldehyde and quaternium-15 in cosmetics, are highly effective public health measures.

Indexed as

Dermatitis, Allergic ContactFormaldehydePreservatives, PharmaceuticalDioxanesHumansHydantoinsMethenaminePrevalencePropylene GlycolsUrea1,3-dimethylol-5,5-dimethylhydantoin5-bromo-5-nitro-1,3-dioxanediazolidinylureaDioxanesFormaldehydeHydantoinsimidazolidinyl ureaMethenaminePreservatives, PharmaceuticalPropylene Glycolsquaternium-15Ureaallergic contact dermatitiscontact allergydermatitisformaldehydeformaldehyde releaserspreservative

Identifiers

PMID42035787
PMCPMC13327177

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.