Allergic contact dermatitis from carmine in cosmetic blush.

Although there are many reported cases of immediate allergy after ingestion of foods containing cochineal, there are few reports of allergic contact dermatitis from carmine. We present a rare case of allergic contact dermatitis due to carmine. A 52-year-old female presented with an itchy erythema on her cheeks at the site where blush had been applied. Patch-tested with her cosmetics, she showed a positive reaction to the blush (30% in petrolatum) and to 0.2% (but not 0.1%) carmine in petrolatum. In this case, the optimum patch-test concentration of carmine was 0.2% in petrolatum.