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.