Peripheral neuropathy is not the end but the beginning

Background: Diagnosing the etiology of peripheral neuropathy is a challenging clinical situation especially in a patient with multiple potential causes. This case discusses how distribution of the neuropathy and accompanying manifestations can help unmask the original culprit.
Case report: A 59-year-old male patient with a 15 year history of diabetes presented with severe peripheral neuropathy affecting the upper more than lower limbs. Six months prior to this presentation he had been diagnosed with hepatitis C infection for which he received interferon, ribavirin and sofosbuvir therapy. Physical examination revealed bilateral, thickened and tender ulnar and popliteal nerves, multiple patches of vitiligo and another well defined, hypopigmented, anesthetic lesions appearing over his back and buttocks. Six slit smears were positive for Mycobacterium leprae and ultrasound of both median nerves indicated swollen and hypoechoic areas along their course with positive intraneural Doppler uptake.
Conclusion: Treatment with the interferon or immunosuppressive therapy could unmask leprosy. Leprosy should be included in the differential diagnosis of severe peripheral neuropathy.