Allergy to balsam of pine and/or spruce was found in 5.5% of 1,247 patients examined with routine patch tests. The majority of the patients proved sensitive to both balsams.
Many of these patients were also allergic to balsam of Peru, Tolu, storax or benzoin.
Only in a minor number of cases could oil of turpentine and colophony be held responsible for allergy to balsam of pine and spruce.
FREGERT S, RORSMAN H. Hypersensitivity to Balsam of Pine and Spruce. Arch Dermatol. 1963;87(6):693–695. doi:10.1001/archderm.1963.01590180021004