Butterfly sign

The importance of irritation from scratching in hyperpigmentation with chronic, itchy jaundice is suggested by the frequent development of a butterfly-shaped area of lesser pigmentation over the back, where the patient cannot easily reach to scratch. We noted this sign in 12 of 17 patients with primary biliary cirrhosis who had chronic pruritus, in 1 of 2 patients with sclerosing cholangitis, and in 1 patient with carcinoma of the bile duct.