However, a few patients will have persistent pain. The pain is in the region of the previous rash and is exacerbated by gently stroking the affected skin and is relieved by applying pressure to the area. The rubbing of clothing is often very painful. This continuing pain is called postherpetic neuralgia. There is a higher incidence of postherpetic neuralgia in cases of herpes zoster involving the face.
Postherpetic neuralgia is one of the most intractable pain syndromes.
The only medication that has consistently been shown to help a significant number of patients is amitriptyline. Amitriptyline enhances pain-suppressing pathways by blocking the reuptake of serotonin and norepinephrine at the neuronal synapses. Other similar acting agents such as imipramine, desipramine, and maprotiline may also be useful in some patients. Recently, topical agents have gained favor in the treatment of the pain. Two crushed aspirin tablets dissolved in 30 ml of chloroform or diethyl ether applied two or three times a day may help the burning and stinging pain.