Replication of the virus in neural ganglia destroys nerve tissue, causing intense pain along corresponding dermatomes. The pain can be stabbing or burning. Sensitivity to touch may develop. The pain may persist for 30 days to more than 6 months, after the lesions heal. The patient can also experience chronic fatigue, anorexia, weight loss, difficulty concentrating, and depression, and they may become inactive. PHN is more common in women and immunocompromised persons.26
Pain management may require the use of acetaminophen, nonsteroidal anti-inflammatory drugs, anticonvulsant agents, topical medications, tramadol, or oxycodone. According to Mallick-Searle et al,27 first-line treatments include gabapentin or pregabalin; an antidepressant (amitriptyline, nortriptyline, or desipramine); and the lidocaine 5% patch. Tramadol or oxycodone should be a third-line drug and used judiciously because of the potential for dependence. Topical capsaicin 8% may be used but requires frequent reapplication (Table 4).13,27,28
Prevention of varicella
The two different types of vaccine used to prevent varicella (chickenpox) are Varivax® (Varicella Virus Vaccine Live) and ProQuad® (a combination of measles, mumps, rubella, and varicella [MMRV] vaccines). Varivax should be administered subcutaneously to children in two doses: the first dose at age 12 to 15 months and the second dose at age 4 to 6 years. Alternatively, ProQuad can be administered to children aged from 12 months to 12 years. Two doses of MMRV vaccine are recommended and are administered in the same schedule as Varivax.29-31
After age 13 years, children can be vaccinated with the two doses of Varivax, with the doses given at least 28 days apart.10
Varicella vaccine lowers the risk for herpes zoster (shingles) in children and adolescents; however, follow-up study of vaccinated children into adulthood is required to clarify this issue.32
Contraindications to the administration of varicella vaccine are listed in Table 5.
Breakthrough VZV infection. Breakthrough VZV infection is defined as wild-type VZV infection occurring more than 42 days after varicella vaccination. Recipients of varicella vaccine who later become immunosuppressed may be susceptible to episodes of varicella, called breakthrough varicella. Breakthrough varicella is very rare in persons who have had a wild-type varicella infection in the past.
Studies show that breakthrough varicella is common in children who have received only one dose of varicella vaccine, not the recommended two doses.33-35
Breakthrough varicella is usually less severe, with the median number of skin lesions commonly less than 50; the lesions are commonly papules that do not progress to vesicles, so that vesicular lesions are less common. The duration of varicella in vaccinated persons is typically shorter and the incidence of fever lower than in unvaccinated persons.36
Post-exposure prophylaxis. VariZIG® (Varicella Zoster Immune Globulin, Human) is an immunoglobulin preparation available after exposure to VZV. If a person who is susceptible to varicella has close contact with someone who has varicella or herpes zoster, VariZIG can be used for immediate short-term immunity. It has been shown to be 70% to 100% effective if administered 3 to 5 days after exposure. Immunity lasts approximately 3 weeks.10,37