CAS: Chemical Abstract Service Registry Number
Birch tar is obtained from birch (Betula verrucosa). It is a dark brown
liquid that contains phenol, cresol, xylenol, guaiacol, creosol, and
It is used as a component of pharmaceutical preparations.
Rothenberg and Hjorth found that positive patch-test reactions to a
mixture of wood tars consisting of pine, juniper, beech, and birch often
produce false-positive reactions. When a mixture of wood tars is positive,
each tar should be tested individually.
H.W. and N. Hjorth, Allergy to perfumes from toilet soaps
and detergents in patients with dermatitis. Archives of Dermatology,
1968. 97: p. 417.
Lahti, A. and M.
Hannuksela, Immediate contact allergy to birch
leaves and sap. Contact Dermatitis, 1980. 6(7): p. 464-5.
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