Abstract
INTRODUCTION: The epidermis and the nervous system share a common embryologic origin from the ectoderm, which explains the coexistence of neurological and cutaneous findings in several conditions. Beyond genodermatoses, peripheral nerve disorders may influence skin appendages, including the nails and hair follicles. Lumbar disc herniation, most commonly occurring at the L4-L5 and L5-S1 levels, can result in chronic compression of nerve roots innervating the dorsal and lateral aspects of the foot. Prolonged neuropathic involvement in this region may lead to subtle but clinically relevant nail changes. This study aimed to evaluate characteristic neuropathy-associated nail alterations in patients with L5-S1 disc herniation and to highlight their potential relevance as indicators of neuropathic involvement. METHODS: This observational study included 20 patients with radiologically confirmed L5-S1 disc herniation who presented with localized thickening and discoloration of the nail plate involving the first and fifth toenails. All patients underwent dermatological and neurological examination. Onychomycosis was excluded in all cases through mycological testing. RESULTS: Nail changes were consistently localized to the hallux and fifth toenail. No history of trauma, fungal infection, or primary dermatological disease was identified. The anatomical distribution of the nail findings corresponded to regions innervated by the affected nerve roots. CONCLUSION: Hyperkeratosis and discoloration of the first and fifth toenails in patients with L5-S1 disc herniation may reflect neuropathic influence on nail morphology. These findings may serve as clinically useful markers for identifying the level of nerve root involvement.