Distinguishing erythrodermic actinic reticuloid from Sézary syndrome

Erythrodermic actinic reticuloid refers to a severe form of actinic reticuloid characterized by a generalized erythroderma and it bears a close resemblance to Sézary syndrome both clinically and hemato-pathologically. We herein report two cases of erythrodermic actinic reticuloid. The diagnosis was made based on the following findings: the absolute number of atypical cells in the peripheral blood were less than 1000/mm³, CD8+ T cells were predominant in both the peripheral blood and skin specimens, phototests of UVA, UVB and visible light were positive, and lymphadenopathy was pathologically dermatopathic. In addition, in case 1, no clonal T cell proliferation based on T cell receptor gene analysis was observed. In light of these findings, the differential diagnosis regarding erythrodermic actinic reticuloid and Sézary syndrome is discussed.