Treatment of long-standing complex regional pain syndrome (CRPS) is empirical and often of limited efficacy. Preliminary data suggest that the immune system is involved in sustaining this condition and that treatment with low-dose intravenous immunoglobulin (IVIG) may substantially reduce pain in some patients.

To evaluate the efficacy of IVIG in patients with longstanding CRPS under randomized, controlled conditions.

A randomized, double-blind, placebo-controlled crossover trial. (National Research Registry number: N0263177713; International Standard Randomised Controlled Trial Number Registry: 63918259)

University College London Hospitals Pain Management Centre.

Persons who had pain intensity greater than 4 …