Rapid improvement of psoriasis vulgaris during drug-induced agranulocytosis

The role of neutrophils in psoriasis has long been discussed. We report a p atient with long-standing psoriasis vulgaris who showed rapid improvement d uring agranulocytosis caused by ticlopidine. The patient did not develop an y new psoriatic lesions for several days, although neutrophils increased da ily after the administration of ticlopidine was stopped. The day after the peripheral blood neutrophil count recovered, several psoriatic plaques reap peared. The correlation of psoriatic activity with peripheral blood neutrop hil counts suggests that a certain number of neutrophils may be required to initiate and maintain psoriasis.