Primary prevention In 1995, the Food and Drug Administration (FDA) approved the Varicella vaccine to prevent chickenpox. Its effect on<unk>  is still unknown. The vaccine—made from a weakened form of the varicella-zoster virus—may keep chickenpox from occurring in nonimmune children and adults, or at least lessen the risk of the varicella zoster virus lying dormant in the body and reactivating later as shingles. If shingles could be prevented,<unk>  could be completely avoided. In May 2006 the Advisory Committee on Immunization Practices approved a new vaccine by Merck (Zostavax) against shingles. This vaccine is a more potent version of the chickenpox vaccine, and evidence shows that it reduces the incidence of<unk> . The CDC recommends use of this vaccine in all persons over 60 years old. The most effective means of preventing<unk>  from a herpes zoster infection is prior vaccination with the varicella vaccine. Vaccination decreases the overall incidence of virus reactivation but also decreases the severity of disease development and incidence of<unk>  if reactivation does occur. Secondary prevention A 2013 Cochrane meta-analysis of 6 randomized controlled trials (RCTs) investigating oral antiviral medications given within 72 hours after the onset of herpes zoster rash in immunocompetent people for preventing<unk>  <unk>  found no significant difference between placebo and acyclovir. Additionally, there was no significant difference in preventing the incidence of<unk>  found in the one RCT included in the meta-analysis that compared placebo to oral famciclovir treatment within 72 hours of HZ rash onset. Studies using valacyclovir treatment were not included in the meta-analysis.<unk>  was defined as pain at the site of the dermatomic rash at 120 days after the onset of rash, and incidence was evaluated at 1, 4, and 6 months after rash onset. Patients who are prescribed oral antiviral agents after the onset of rash should be informed that their chances of developing<unk>  are no different than those not taking oral antiviral agents.
Postherpetic neuralgia
Trigeminal neuralgia
Atypical trigeminal neuralgia
Occipital neuralgia
Erythromelalgia
Morning sickness
Cold-stimulus headache
Cerebritis