Prurigo Nodularis in Lepromatous Leprosy: A Manifestation of Neuropathic Pruritus and Denervation Dermatopathy

A 54-year-old male with lepromatous leprosy (LL) on multidrug therapy for the past 10 months and a history of disease for the past 5 years presented with multiple persistent pruritic nodules on his legs for 6 months. Examination showed hyperpigmented, firm nodules with central depigmentation on ichthyotic skin on the extensor aspect of both lower limbs, and glove-and-stocking anesthesia [Figure 1]. Histopathology was consistent with prurigo nodularis (PN) [Figure 2]. Nerve conduction study with sympathetic skin response (SSR) revealed an absent sensory neural action potential in the left ulnar and both sural nerves, reduced compound motor action potential (CMAP) in the right peroneal nerve, and absent CMAP in the left ulnar nerve, with absent SSR in all limbs, suggestive of sensorimotor axonal polyneuropathy and small fiber neuropathy. Treatment with topical clobetasol proprionate 0.05% cream once daily and pregabalin 75 mg/day led to improvement in signs and symptoms of PN at 8-weeks follow-up.Figure 1: Diagnosed case of lepromatous leprosy with multiple hyperpigmented, firm nodules with central depigmentation on a background of ichthyosis distributed symmetrically on the extensor surfaces of the lower limbsFigure 2: (a): Histopathological evaluation of the lesions showed a hyperplastic epidermis with parakeratosis, compact orthokeratosis, irregular acanthosis with blunt rete ridges, and focal basal cell vacuolization (Hematoxylin and eosin, 10×); (b) The dermis showed moderate perivascular lymphomononuclear inflammation along with perpendicularly oriented collagen fibers in the papillary dermis (Hematoxylin and eosin, 40×)Lesions mimicking PN have been described in cases of LL and histoid leprosy previously.[1-3] Histoid leprosy was ruled out by the absence of any histopathological findings of histoid. The occurrence of PN in the context of LL presents a clinical paradox, where pruritus emerges despite the expected anesthetic milieu, underscoring the complex interplay between neural involvement, immune dysregulation, and chronic inflammatory pathways.[4] Authors’ contributions We confirm that all authors have read and approved the manuscript for submission. All authors meet authorship criteria, and the manuscript represents honest work. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Use of artificial intelligence (AI) We have not used artificial intelligence.