A Rare Presentation of Lateral Cutaneous Nerve Neuralgia with Dermatitis following PD-1 Inhibitor Therapy

Lateral cutaneous nerve neuralgia (LCNN), clinically characterized by burning sensation, cold sensitivity, deep muscle achiness, tingling, numbness, localized anesthesia, and hair loss in the anterolateral thigh. However, LCNN is rarely associated with cutaneous manifestations, and significant LCNN-associated dermatitis has not previously been reported.

Here, we present a case of dermatitis occurring in a region affected by LCNN following melanoma treatment. The patient achieved complete resolution of cutaneous lesions and partial improvement of neurological symptoms after 1 month of treatment with oral mecobalamin and neurotropin, combined with topical glucocorticoid therapy.

This presentation may represent a rare immune-related adverse event associated with PD-1 inhibitor therapy.