Occupational pigmented contact dermatitis from azo-dyes

A 51-year-old man had been working in a dye factory for 25 years and had noticed itching and pigmentation on the extremities for the past 5 years. Patch testing showed positive reactions to Sudan I and Vacanceine Red, among the azo dyes which he had been handling. After he changed his work, he became free from erythematous lesions with itching. The pigmentation almost disappeared 10 months later.