Lymphocyte kinetics in pustular psoriasis.

Generalized pustular psoriasis is a potentially lethal variant of psoriasis vulgaris characterized by the appearance of sterile pustules on inflamed psoriatic skin. We now report the finding of an absolute lymphopenia at the onset of pustular psoriasis. While the white blood cell count rises to a level of 25,000 to 40,000 in the initial stages of a pustular flare, the lymphocyte count drops from a normal level to an absolute lymphopenia. This "lymphocyte eclipse," as we have called it, appears to be a reliable sign of impending pustular activity and has now been documented in ten patients with pustular psoriasis. Immediate institution of therapy may abort a potentially lethal complication of psoriasis.