Diagnostic utility of skin autofluorescence when patch test results are doubtful.

ABSTRACT

BACKGROUND: The standard diagnostic test for allergic contact dermatitis is the patch test, which can also be used to identify irritant contact dermatitis. Doubtful reactions (?+) can be often clinically relevant to individuals and can require additional tests. OBJECTIVES: The purpose of this study was to examine whether autofluorescence (AF) measurements in patients with doubtful reactions are helpful in diagnosing contact dermatitis. METHODS: Patients with a history of contact dermatitis were patch tested on the upper back for 48-hours of occlusion using aqueous solutions of 5% sodium lauryl sulfate. Reaction intensity was scored, and AF was measured on reactive lesions and non-lesions. Three dermatologists classified the results as positive or negative using the fluorescence photographs of patients with a doubtful reaction. RESULTS: Among doubtful reactions, the R/G% values were significantly higher in the AF- based positive group than in the negative group (P = .0086). On the other hand, the heterogeneity values of R, G, and B (HR, HG, HB) were significantly lower in the AF-based positive group (P = .0026, .0046, .0004 respectively). CONCLUSIONS: Measuring AF along with the clinical readings can help confirm doubtful patch test reactions.