Peripheral nerve block with a high concentration of tetracaine dissolved in bupivacaine for intractable post-herpetic itch: a case report

Background Post-herpetic itch (PHI) is a neuropathic itch syndrome following herpes zoster. It has been reported that PHI is occasionally sufficiently severe to compromise patients' quality of life and frequently refractory to treatment. Here, we present a case of severe chronic PHI successfully treated with supraorbital nerve block using a high concentration of tetracaine dissolved in bupivacaine. Case presentation An 82-year-old man presented with severe chronic itching in the ophthalmic branch of the left trigeminal nerve dermatome, following acute herpes zoster. The patient's itching was unresponsive to usual medical treatments for PHI including antiepileptic drugs, topical capsaicin cream, and supraorbital nerve radiofrequency thermo-coagulation. Topical lidocaine cream could relieve the itching, but could not provide long-term relief of itching and thus failed to achieve a satisfactory result. After these conventional treatments, left supraorbital nerve block using 4% tetracaine dissolved with 0.5% bupivacaine was conducted. Afterwards, the patient experienced long-lasting resolution of the itching with improvement of sleep disturbance. A transient, mild edema of the eyelids occurred, but there were no other complications. Conclusions Peripheral nerve block using 4% tetracaine dissolved with 0.5% bupivacaine was beneficial in relieving PHI in the ophthalmic division of the trigeminal nerve.