Persistent erythema and pruritus, with a confluent histiocytic skin infiltrate, following the use of a hydroxyethylstarch plasma expander.

A 40-year-old woman developed a persistent pruritus with erythema of the head and upper trunk, which started within 2 weeks of a hydroxyethylstarch (HES) infusion and was still present 2 years later. Histological examination demonstrated a striking dermal infiltrate of KP1-positive foamy macrophages which had electron-lucent vacuoles. The timing of the onset, the body site distribution, the exclusion of other possibilities and an appropriate history of high dosage HES infusion, suggested that this was the cause of the eruption. Staining with periodic acid-Schiff (PAS) surprisingly was negative but we could not stain HES in vitro with this histochemical stain, and we postulate that the unique extent of the infiltrate and the negative PAS stain in our patient may indicate an impaired ability to degrade this chemical. This may be an important factor in the poorly understood pathogenesis of persistent pruritus induced by HES.