Herpes zoster (HZ) results from reactivation of the latent varicella zoster virus in sensory ganglia, with characteristic symptom of painful skin rash and localized blisters. Usually, the rash heals and pain resolves within two to four weeks, but in some patients the pain continues to persist for more than 90 days after the onset of rash, which is known as postherpetic neuralgia (PHN).~PHN is the most common complication of HZ. Depending on the definition, the incidence of HZ patients developing PHN varied from approximately 5% to 30%. The continued pain or paresthesia not only affects patient quality of life, but also causes physical disability, emotional distress and social isolation. Conventional treatments for PHN include topical lidocaine or capsaicin, anticonvulsants, tricyclic antidepressants, and opioids. However, whether prescribed alone or in combination, these medications are only partially work in some patients or not work at all in others. Once PHN presences, it is often refractory to the treatment, therefore, it is important to prevent the occurrence of PHN. Previous studies have identified age, rash duration before consultation, presence of severe rash and acute pain severity as predictors of increased PHN risk. Thus, the treatment of acute pain of herpes zoster has the potential to prevent the development of PHN.~Acute zoster pain represents a combination of nociceptive and neuropathic pain which can be relieved by oxycodone. However, it is not known whether the additional use of oxycodone therapy to current standard treatment in acute herpes zoster patients will decrease the incidence of post-herpetic neuralgia.
Postherpetic neuralgia (PHN) which persists more than 90 days after the resolution of the acute shingles episode is the most common complication of herpes zoster. The continued pain or paresthesia not only affects patient quality of life, but also causes physical disability, emotional distress and social isolation. Conventional treatments for PHN are only partially work in some patients or not work at all in others. Once PHN presences, it is often refractory to the treatment, therefore, it is important to prevent the occurrence of PHN. In the study, the investigators want to identift whether the additional use of oxycodone therapy to current standard treatment in acute herpes zoster patients will decrease the incidence of post-herpetic neuralgia.