BACKGROUND Leprosy is an infection caused by Mycobacterium leprae. An extensive literature search did not reveal many reports of melioidosis in association with leprosy. CASE REPORT A 22-year-old woman, who was diagnosed with multibacillary leprosy, developed dapsone-induced methemoglobinemia and hemolytic anemia, complicated by melioidosis. Methemoglobinemia was treated with methylene blue and vitamin C. Two weeks of ceftazidime was initiated to treat melioidosis, and the patient was discharged on amoxicillin/clavulanic acid and doxycycline as melioidosis eradication therapy. However, she developed drug-induced hypersensitivity. Trimethoprim/sulfamethoxazole, as an alternative treatment for melioidosis eradication, was commenced and was successfully completed for 12 weeks. During the fifth month of multidrug therapy, the patient developed type II lepra reaction with erythema nodosum leprosum reaction, which was treated with prednisolone. Leprosy treatment continued with clofazimine and ofloxacin, and complete resolution of skin lesions occurred after 12 months of therapy. CONCLUSIONS Our case highlighted the challenges posed in managing a patient with multibacillary leprosy with multiple complications. Clinicians should be aware that dapsone-induced methemoglobinemia and hemolysis might complicate the treatment of leprosy. Our case also highlighted the safety and efficacy of combining ofloxacin and clofazimine as a leprosy treatment regimen in addition to gradual steroid dose titration in the presence of type II lepra reaction.
Dapsone-induced hypersensitivity reactions may cause severe cutaneous adverse reactions, such as drug reaction with eosinophilia and systemic symptoms (DRESS). It has been reported that HLA-B*13:01 is strongly associated with dapsone-induced hypersensitivity reactions among leprosy patients. However, the phenotype specificity and detailed immune mechanism of HLA-B*13:01 remain unclear. We investigated the genetic predisposition, HLA-B*13:01 function, and cytotoxic T cells involved in the pathogenesis of dapsone-induced severe cutaneous adverse reactions. We enrolled patients from Taiwan and Malaysia with DRESS and maculopapular eruption with chronic inflammatory dermatoses. Our results showed that the HLA-B*13:01 allele was present in 85.7% (6/7) of patients with dapsone DRESS (odds ratio = 49.64, 95% confidence interval = 5.89-418.13; corrected P = 2.92 × 10-4) but in only 10.8% (73/677) of general population control individuals in Taiwan. The level of granulysin, the severe cutaneous adverse reaction-specific cytotoxic protein released from cytotoxic T cells, was increased in both the plasma of DRESS patients (36.14 ± 9.02 ng/ml, P < 0.05) and in vitro lymphocyte activation test (71.4%, 5/7 patients) compared with healthy control individuals. Furthermore, dapsone-specific cytotoxic T cells were significantly activated when co-cultured with HLA-B*13:01-expressing antigen presenting cells in the presence of dapsone (3.9-fold increase, compared with cells with no HLA-B*13:01 expression; P < 0.01). This study indicates that HLA-B*13:01 is strongly associated with dapsone DRESS and describes a functional role for the HLA-restricted immune mechanism induced by dapsone.