Immediate contact reactions to fragrance mix constituents and Myroxylon pereirae resin.

We have studied patients who have positive-patch test reactions to fragrance-allergic screening substances fragrance mix (FM) or Myroxylon pereirae resin (balsam of Peru) for immediate contact reactions to the standard FM, the constituents of the FM and Myroxylon pereirae resin. In the fragrance-positive subjects (n = 60), there were positive immediate contact reactions to Myroxylon pereirae resin in 56.6% and to FM in 11.6%. In a control group (n = 50) of eczematous, patch test-negative patients there were positive immediate reactions to Myroxylon pereirae resin in 58.0% subjects and to FM in 12.0%. The absence of a significant difference between the fragrance-allergic group and control group is in keeping with a non-immunological basis for the majority of the immediate reactions seen.