Clinical features of relapse after multidrug therapy for leprosy in China

Background: Although the World Health Organization (WHO) has defined relapse in leprosy, it is often difficult to confirm a relapse, especially in paucibacillary (PB) patients. Objective: To study features of relapse cases in order to determine the information needed to allow better management of relapses in the leprosy control programme. Design: A retrospective survey by questionnaire was carried out at national level at the end of 2012. Results: There were 40 relapsed patients on register. The clinical form of leprosy was TTS, BT4, BB5, BL13 and LL13. Twenty-eight patients had had a positive skin smear test at the start of MDT, with a BI ranging from 0.83 to 6.0. At the time of completing MDT, the skin smear test remained positive in seven patients. After completion of MDT, other family members of 13 patients were identified as new leprosy patients. All relapse cases showed one or more active skin lesions. There were 33 patients with a positive skin smear test at the time of relapse. A total of 23 patients had a biopsy at the time of relapse, including seven patients with a negative skin smear test. The histological features of relapsed BB-LL patients included granulomas containing macrophages or epithelioid cells with sparse lymphocytes and acid-fast bacilli. The histological features of seven patients with negative skin smears showed epithelioid cell granulomas with dense lymphocytes surrounding the granuloma, but without distinct edema in the dermis. The average interval from completion of MDT to the diagnosis of relapse was 168.5 +/- 92.6 months with a range of 21-322 months. During the study, nine patients were tested for rifampicin resistance, but none showed any mutation. Conclusions: Leprosy relapse after MDT usually occurred late and all relapse cases had new active skin lesions. Most patients relapsed with a positive skin smear after previously reaching negative BI status. Relapse with a negative skin smear test should be confirmed very cautiously.