The clinical severity score of chronic actinic dermatitis correlates with in vivo photoallergic reactions and the immunologic parameters related to a shift towards Th2 immunity from the Th2/Th1 balanced status in patients with chronic actinic dermatitis.

Background: Chronic actinic dermatitis (CAD) has a more complicated pathogenetic basis than others. The clinical grading system and its correlations with the clinical and immunological parameters still remained to be investigated to define the nature of CAD in a more detailed manner.

Objectives: We investigated correlations of the clinical severity score of CAD (CSS-CAD) with the clinical and immunological parameters.

Methods: We evaluated 72 patients with CAD and classified them into three groups according to the CSS-CAD. We analysed total IgE level, peripheral blood (PB) eosinophil count, the ratio of Th2cell (CCR4 + CD4 +) percentage over Th1 cell (CXCR3 + CD4 +) percentage (Th2/Th1) and/or the sum of suppressor/cytotoxic T cells.

Results: The total IgE levels and the percentage of PB eosinophils were higher in the severer group than other groups. A shift towards Th2 from Th2/Th1 balanced status may be affected by total counts of suppressor T cells, and the patient with higher Th2/Th1 ratio than balanced status had the more proportion in the severer CSS-CAD group than other groups.

Conclusion: The CSS-CAD correlates with total IgE level, PB eosinophil count and a shift towards Th2 immunity from Th2/Th1. So we suggest the Th1/Th2 dysbalance may be affected by the CSS-CAD.