Management of nodular prurigo has been less than satisfactory. Conventional therapies such as systemic antihistamines and topical steroids have not been particularly successful. The effects of narrow-band ultraviolet B (NB-UVB) phototherapy in the treatment of various inflammatory dermatoses have been proven, however, no data exist on the efficacy and the duration of remission in NB-UVB monotherapy for nodular prurigo. The aim of this study was to evaluate the effect of NB-UVB phototherapy on recalcitrant nodular prurigo. NB-UVB phototherapy was performed once a week on 10 patients with recalcitrant nodular prurigo. The initial dose was 0.4 J/cm(2), and the dose was increased by 0.1 J/cm(2) for each treatment. The treatment was performed until the eruption was almost clear. In each patient, a mean cumulative dose of 23.88 J/cm(2) was applied over a mean of 24.3 irradiations. The mean maximum daily dose of ultraviolet B was 1.2 +/- 0.4 J/cm(2). NB-UVB phototherapy notably improved the eruption of nodular prurigo in all patients. Follow up at 1 year revealed that only one patient had relapsed. The remaining nine patients continued to derive long-term benefits. NB-UVB phototherapy appears to be an effective treatment for recalcitrant nodular prurigo, offering long-term benefits in the majority of those treated.