Chemical substances and contact allergy--244 substances ranked according to allergenic potency

From 1985 to 2001 a group consisting of thirty experts including dermatologists from universities, representatives from the chemical industry and from regulatory authorities elaborated and consequently decided on the potency ranking of chemicals with contact allergenic properties. These chemicals were defined either as synthetic chemicals or as chemicals identified as ingredients in natural products. On 244 substances clinical and experimental data on humans and results of animal tests as documented in the scientific literature were carefully collected and evaluated. This careful evaluation and assessment of these chemicals clearly demonstrate that ranking of substances according to their allergenic potency is possible and justified. It was decided to rank the most potent contact allergens in Category A of substances having significant allergenic properties. Substances with a solid-based indication of a contact allergenic potential and substances with the capacity of cross-reactions were listed in Category B and substances with insignificant or questionable allergenic effects were listed in Category C. An assessment of these compiled data is published here. Three Appendices give a comprehensive overview of the 98 substances listed in Category A, the 77 substances listed in Category B and the 69 substances listed in Category C.