1 514 781 patients shows methylisothiazolinone allergy prevalence is 5.48% in dermatitis cases

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Contact dermatitis Published June 5, 2026 Medically reviewed June 5, 2026 Study authors: Isufi Daniel, Karimian Kian, Jensen Mikkel Bak, Larsen Christoffer Kursawe, Søgaard Rebekka, Johanse… PubMed ↗ DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Note regional variations and increased benzisothiazolinone use requiring enhanced surveillance in dermatitis patients.

This systematic review and meta-analysis assessed the prevalence of contact allergy to isothiazolinones among 1 514 781 dermatitis patients. Data were sourced from PubMed, Embase, and Web of Science covering the period from 2000 to 2025. The primary outcome measured the prevalence of contact allergy to these specific substances.

The analysis reported a pooled prevalence of 5.48% for methylisothiazolinone. Methylchloroisothiazolinone/methylisothiazolinone showed a prevalence of 4.58%, while benzisothiazolinone showed a prevalence of 2.09%. Clinical relevance was observed in 55.6% of methylisothiazolinone cases, 60.1% of methylchloroisothiazolinone/methylisothiazolinone cases, and 35.3% of benzisothiazolinone cases.

The authors highlight substantial regional variations in usage patterns dependent on regulatory strictness. There is an indication of a decline particularly regarding methylisothiazolinone and methylchloroisothiazolinone/methylisothiazolinone. Conversely, there is an increase in the use of substances such as benzisothiazolinone necessitating enhanced surveillance measures. No adverse events or discontinuations were reported in this review.

The findings support the efficacy of proactive risk management for post-marketed substances. However, the study does not report causality or specific confidence intervals for the prevalence estimates.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJun 2026

PMID41804652

View Original Abstract ↓

Isothiazolinones are employed in the preservation of cosmetic, consumer and industrial products, with the objective of preventing deterioration and spoilage. However, the utilization of isothiazolinones is associated with an elevated risk of developing contact allergy (CA). Herein, we assess the epidemiology of CA to isothiazolinones among dermatitis patients from year 2000 onwards. We systematically searched PubMed, Embase, and Web of Science from 1 January 2000 to 19 April 2025 yielding 115 studies comprising 1 514 781 dermatitis patients. The prevalence of CA to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was 4.58%, methylisothiazolinone (MI) was 5.48%, and benzisothiazolinone (BIT) was 2.09%. The clinical relevance ranged from 60.1% for MCI/MI, 55.6% for MI, and 35.3% for BIT. Asia and North and South America exhibited the highest rates of CA to isothiazolinones, whereas Europe showed lower rates. These findings underscore the efficacy of proactive risk management for post-marketed substances such as MI, underscoring substantial regional variations in usage patterns, which are contingent on the strictness or permissiveness of their incorporation into everyday consumer products. There is an indication of a decline, particularly regarding MI and MCI/MI. However, there has been an increase in the use of substances such as BIT, which necessitates enhanced surveillance measures.