[Occupational dermatitis due to a yellow quinophthalone dye (solvent yellow 33: C.I. 47 000)]

An occupational allergic contact dermatitis caused by a yellow quinophthalone dye which is used for colored smokes in detonators was the reason for further studies of this case of allergy. Solvent Yellow 33 (German: Rauchgelb) belongs to the groups of quinaldine dyes which are produced by condensing quinaldine and phthalic anhydride. The dye itself is a mixture of 67% unsubstituted quinophthalone and 33% 6-methylquinophthalone (Colour Index 47 000). Quinophthalone derivatives are widespread in technology and industry and are used as yellow dyes in food (pudding), plastics (PVC), textile goods (nylon) and cosmetics (lipsticks, make-up). Cases of contact sensitization due to quinophthalone dyes are seldom recognized. Sensitizing experiments in guinea pigs were unsuccessful. Therefore Solvent Yellow 33 must be considered a weak sensitizer.