Acute Erythroderma as an Exclusion Criterion for Idiopathic CD4+ T Lymphocytopenia

Background:  Idiopathic CD4⁺ T lymphocytopenia is defined as a CD4⁺ T lymphocytopenia of less than 0.3X10⁹/L that is not associated with human immunodeficiency virus, other immunodeficiency, or immunosuppressive therapy. The associated clinical course and laboratory findings are variable. We describe a subset of patients whose peripheral CD4⁺ T-lymphocytopenia was transient, and suggest a pathomechanism for this phenomenon.

Observations:  We describe three patients with cutaneous T-cell lymphoma, atopic dermatitis, or psoriasis in whom acute erythroderma was concomitant with a peripheral CD4⁺ T lymphocytopenia that normalized after resolution of the erythroderma. Immunoperoxidase staining of skin biopsy specimens and quantitative estimation of CD4⁺ T lymphocytes in the cutane- ous and peripheral blood compartments demonstrated that the peripheral CD4⁺ T lymphocytopenia in these cases most probably resulted from sequestration of CD4⁺ T lymphocytes in the skin. The skin of an erythrodermic patient appears capable of sequestering 10¹⁰ to 10¹¹ CD4⁺ T lymphocytes, whereas the peripheral blood compartment contains in the range of 10⁹ CD4⁺ T lymphocytes.

Conclusions:  We propose that CD4⁺ T lymphocytopenia can occur as a result of acute erythroderma of multiple causes and that acute erythroderma associated with transient CD4⁺ T lymphocytopenia be considered as an exclusion criterion for idiopathic peripheral blood CD4⁺ T lymphocytopenia.(Arch Dermatol. 1994;130:1530-1533)