Allergic contact dermatitis from rosin used as soldering flux

Two cases of allergic contact dermatitis from soldering fluxes are reported. Both were caused by rosin (colophony). One case was confirmed by a positive patch test to rosin purchased from a commercial European patch test supplier. The other could be confirmed only by a positive patch test to the specific rosin used to flux the solder; repeated patch tests to rosin purchased from the same European supplier were negative. Dermatitis from soldering fluxes is reviewed.