Nickel earlobe dermatitis and clinical non-relevance of the oral exposure.

Objective: Nickel is the most common cause of allergic contact dermatitis (ACD). Because nickel restriction is commonly imposed on many patients with the only earlobe ACD to nickel hypersensitivity, the aim of this study was to identify the role of occasional and extended oral nickel exposure in these patients.

Design: This is a case-control study.

Subjects: Thirty-four outpatients, previously diagnosed as monosensitized to nickel, suffering from earlobe dermatitis were enrolled; 11 of them showed active dermatitis. The control group consisted of six healthy (non-nickel-sensitive) subjects.

Interventions: High oral nickel challenge (20 mg) and protracted oral challenge (1 mg once a day). Observation period: 6 weeks.

Results: Clinical earlobe lesions were not affected by a high oral nickel intake nor by a protracted oral challenge.

Conclusions: Dietary nickel restriction seems to be useless in patients with earlobe ACD due to nickel hypersensitivity.