From 1980 to 1993, 379 hairdressers were studied in the outpatient clinic of our department. All were patch tested with a standard screening tray and specific hairdressing products. Most of the workers assessed were women (92.3%) with a mean age of 21.33 years. A positive patch test response to one or more of the allergens tested was presented by 58.8%. Allergic contact dermatitis was diagnosed in 48.8%. The mean frequencies of sensitization ranked as follows:p-phenylenediamine base, 45.9%; nickel, 41.4%; disperse orange 3,32.7%; and 4-aminoazobenzene, 31.9%. Finally, the risk of contact dermatitis is indicated among these workers and their sensitization, while still young, after only a few years in the trade.