A case of occupational dermatitis in a 65-year-old beekeeper is reported. A positive patch test with a mixture of balsams led to testing with beeswax from his own hives and with leaves and resins from poplar trees. These tests were also found strongly positive in accordance with earlier reports.
Honeybees employ plant resins, including poplar and fir resins, in the construction of their combs; thus the contact between plant resin and beekeeper is established. A series of control tests made support the view that the cutaneous allergy to poplar resins encountered in the patient was of an allergic and not of a primary irritant nature.
Finally a tentative explanation of the crossallergies between balsam of Peru and poplar resins found in the patient and reported in the literature is presented.
Rothenborg HW. Occupational Dermatitis in Beekeeper Due to Poplar Resins in Beeswax. Arch Dermatol. 1967;95(4):381-384. doi:10.1001/archderm.1967.01600340041008