Although atopic dermatitis generally responds to topical therapy, small numbers of patients have severe resistant disease despite second-line therapies. High-dose intravenous immunoglobulin has been suggested to be of benefit in a small number of reports. We have conducted an open, single-centre study of adjunctive high-dose intravenous immunoglobulin (Flebogamma 5%). Six patients received treatment at 2 g kg(-1) month(-1) for 6 cycles, with a 3-month follow-up period. Skin scores, lymphocyte phenotypes and intracellular cytokine analysis were performed. Four of six patients had major improvements in skin scores and the overall reduction was significant (p = 0.035). CD4+ T-cell numbers fell following high-dose intravenous immunoglobulin infusions, recovering by the next cycle. T-cell CD69 expression decreased to 60% of baseline values. Reductions in the proinflammatory cytokines IFN-gamma and TNF-alpha were non-significant. Adjunctive high-dose intravenous immunoglobulin may be a useful therapeutic approach in adults with severe treatment-resistant atopic dermatitis, but it will require further assessment in randomized controlled trials to establish this.