The 24 contact allergens are presented which produced positive patch test reactions in 3% or more of the patient population of the New York University Skin and Cancer Unit during the years 1968 to 1970. The ten most common among these were mercury bichloride, mercaptobenzothiazole, paraphenylenediamine, potassium dichromate, ethylenediamine, nickel sulfate, turpentine oil, formaldehyde solution, poison ivy, and bismarck brown. Some of the sources of exposure to these allergens and some of the known cross-sensitizing compounds are listed. The clinical significance of strong vs weak patch test reactions is discussed.
Baer RL, Ramsey DL. The Most Common Contact Allergens. Arch Dermatol. 1973;108(1):74-78. doi:10.1001/archderm.1973.01620220046011