Repeat insult patch testing of the quinoline dyes, D & C Yellow No. 10 (Acid Yellow No. 3) and D & C Yellow No. 11 (Solvent Yellow No. 33) demonstrated that concentrations as high as 1,000 ppm of the former induced no delayed contact hypersensitivity, whereas, concentrations of 20 ppm and 10 ppm of D & C Yellow No. 11 induced delayed hypersensitivity reactions in human volunteer panelists. No definitive hypersensitivity resulted from testing with 5 ppm of this dye. 2 persons who had been demonstrated to have reacted allergically to the use of a soap bar that contained D & C Yellow No. 11 did not react to the ad libitum use of a soap bar in which this dye was replaced with D & C Yellow No. 10.
