Contact dermatitis from methylisothiazolinone in a paint factory

Area of Science:

• Dermatology
• Toxicology
• Occupational Health

Background:

• New chemicals, including preservatives, can trigger widespread contact dermatitis.
• Methylisothiazolinone (MI), a new preservative, is now used in paints, glues, and cosmetics in the EU.

Observation:

• A factory outbreak of allergic contact dermatitis occurred among 14 paint manufacturing workers.
• Four workers developed allergic contact dermatitis specifically to MI.

Findings:

• Patch tests confirmed positive reactions to MI and its combination with methylchloroisothiazolinone (MCI/MI).
• Stronger reactions to MI than MCI/MI suggest primary sensitization to MI.
• MI demonstrates potential for eliciting and inducing human contact allergy.

Implications:

• The widespread use of MI in consumer products necessitates careful monitoring.
• Understanding MI sensitization patterns is crucial given its continued use with MCI.
• Further research is required to evaluate the safety of MI in cosmetics for a large consumer base.