[Epicutaneous sensitization to metals and contact allergic dermatitis: analysis of an ambulatory caseload]

We have retrospectively analyzed the clinical and anamnestic features of 233 out-patients (197 females and 36 males; mean age: 33 years; SD: +/- 13.3) with epicutaneous sensitization to metals, who had been examined at the department of allergology of our institution during one year. Among females, nickel sulphate was the metallic salt which most frequently resulted positive at patch testing (87.8% of cases), followed by cobalt chloride (23.6%) and potassium bichromate (10.2%). Nickel was the most common sensitizing metal also in males (58.3%), among whom sensitization to chromate resulted second in order of frequency (30.6%), and sensitization to cobalt was relatively rare (11.1%). In selected cases, the utilization of additional, specific series allowed to document rare cases of sensitization to metallic salts not included in the standard patch test series (copper sulphate, cadmium chloride, zinc stearate, phenylmercuric nitrate). 78 patients were sensitized to more than one metal. Skin sensitivity to metals was often linked to allergic disease familiarity and/or to sensitization toward type I allergens. Allergic contact dermatitis was diagnosed in 80 patients: cutaneous manifestations had been present on average for over four years, sometimes in generalized or persistent form. An occupational contact with the causative metals was identified in 15 cases. However, the occupational origin of the disease could never be documented with certainty, due to concomitance of frequent non-occupational exposures and to lack of information on pre-employment skin sensitivity status. Thus, the value of patch testing, during both pre-employment screening and health surveillance, is emphasized.