Postherpetic itch (PHI), a common condition in neuropathic itch is not as well studied as postherpetic neuralgia. Intractable PHI is thought to be hyperexcitability of itch-transmission nervous system caused by neural injury from herpes zoster. In some cases, PHI is very severe to compromise patient’s quality of life and refractory to conventional treatments. Here, it is reported that a case of severe chronic PHI was reduced with trigeminal ganglion blocks and thymosin alpha 1 injections. A 74-year-old man complained of severe itching with hypoesthesia in his left eyebrow and scalp for 5 years after the initial onset of herpes zoster at the same site, despite treatment with two types of antihistamines, gabapentin, and amitriptyline. He developed ulcers on his forehead and scalp because of his scratching. Trigeminal ganglion blocks and thymosin alpha 1 injections reduced itching, with the ulcers disappearing within 1 month. In this case, it is suggested that trigeminal ganglion blocks and thymosin alpha 1 injection may be a useful treatment option for PHI.