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Sensitization to dimethyl fumarate with multiple concurrent patch test reactions


  • Conflicts of interest: The authors have declared no conflicts.

Kaija Lammintausta
Department of Dermatology
Turku University Hospital
PO Box 52, 20521 Turku
Tel: 358-2-3131609
Fax: 358-2-3133328


Background: Chairs and sofas imported from China to Europe were shown to contain dimethyl fumarate (DMF), a sensitizing, volatile chemical. Many of the sensitized patients also had positive patch test reactions to acrylates.

Objectives: To analyse the occurrence and strength of DMF sensitization and the appearance of concomitant reactions.

Methods: Patch testing with DMF in concentrations of 0.1–0.00001% was carried out in 37 patients. Diethyl fumarate (DEF), diethyl maleate (DEM), dimethyl maleate (DMM), ethyl acrylate (EA), methyl acrylate (MA), and methyl methacrylate (MMA) were also tested with a dilution series at equimolar concentrations.

Results: The lowest concentration of DMF eliciting a reaction varied between 0.0001% and 0.1% and all but four patients reacted concurrently to DEF. DEM elicited positive patch test reactions in 21/37 patients and DMM reactions were seen in all 9 patients tested. EA elicited positive reactions in 13/37 patients and a positive MA reaction was seen in 7/37 patients, 2 of whom also reacted to MMA.

Conclusions: The strength of the sensitization to DMF showed variation and concurrent reactions were common. Concurrent reactions to (meth)acrylates were seen in patients, who reacted to lower (0.001% or less) DMF concentration probably elicited by cross-reactivity.