Hyposensitization and desensitization in allergic contact dermatitis

Background: Acquired allergic contact dermatitis (ACD) causes significant morbidity. Certain occupations predispose workers to ACD, especially those that may damage the skin barrier. Allergic contact dermatitis has significant socioeconomic effects. Allergic contact dermatitis is difficult to treat, particularly if exposure is unavoidable. Objective: The objective of this study was to establish the efficacy of intradermal steroid injections in inducing specific antigen hyposensitization when administered weekly into shifted patch-test sites. Methods: Prospective, open-label trial included 10 patients with ACD. Each week for up to 8 weeks, patients were patch-tested to their known allergen, and the patch-test site was injected with triamcinolone. Primary outcomes were clinical score, reaction size, erythema, and thermal characteristics. Statistical analysis included regression, correlation, repeated measures, and analysis of variance with contrast variables. Results: Overall results suggest significant decreases in patch-testing reactions as evidenced by improved clinical scores, reaction sizes, and reduced heat production. In 3 patients, the patch test became negative. This desensitized state persisted for 2 months in 1 patient and for 4 months in the other 2 patients. Conclusions: Repetitive treatments of weekly, shifted, positive patch test sites with intradermal steroid injections show a tendency toward allergen-specific hyposensitivity and in some cases to nonreactivity at repeat patch testing. This finding may influence future management of ACD.