Erythema nodosum leprosum (type 2 reaction) in a patient with neurofibromatosis type 1

Being a region endemic for leprosy, clinical practitioners in India often encounter myriad manifestations and diverse complications of the disease. However, the masking of the obvious clinical presentations due to the coexistence of a closely resembling unrelated disorder, a 'mimicker', would indeed pose a serious diagnostic predicament unless a high degree of clinical suspicion is maintained. Leprosy, also known as Hansen's disease is a chronic infectious disease caused by Mycobacterium leprae complex that involves the skin and peripheral nerves. Neurofibromatosis type 1 (NF1) also known as von Recklinghausen's disease is an autosomal dominant genetic disorder that presents with skin changes and benign peripheral nerve sheath tumours called neurofibromas. Here, we present the case of a 35-year-old man with NF1 who presented with type 2 lepra reaction (erythema nodosum leprosum, ENL) and the skin biopsy unmasked ENL nodule among the group of NF1 nodules.