Herpes zoster: a case and review

The aetiology, epidemiology, and investigative management of herpes zoster (shingles). The patient details have been changed and anonymised to protect the identity of the individual.

1. Herpes Zoster Why the cat came back

2. Are zoster rates increasing? Immunization? In the U.S. population older than 65 years, age-specific HZ incidence increased 39% from 10.0 per 1000 person-years in 1992 to 13.9 per 1000 person-years in 2010 with no evidence of a statistically significant change in the rate of increase after introduction of the varicella vaccination program. Introduction and widespread use of the vaccine did not seem to affect this increase. Image from:   http://annals.org/article.aspx?articleid=1784289

3. Epidemiology The incidence of HZ remains stable as the incidence of varicella is decreasing: In one US HMO: Age-adjusted and -specific annual incidence rates of HZ fluctuated slightly over time; the age-adjusted rate was highest, at 4.05 cases/1000 person-years, in 1992, and was 3.71 cases/1000 person-years in 2002. The age-adjusted rates decreased from 2.63 cases/1000 person-years during 1995 to 0.92 cases/1000 person-years during 2002; there was a 75% decrease in children 1-4 years old between 1992-1996 and 2002. Vaccinated children are less likely to become infected with wild-type chickenpox virus, which is more likely to reactivate as shingles compared to attenuated vaccine virus. Reassuring for countries considering universal varicella vaccination.

4. I have Zoster at 41 – am I immunocompromised? Almost 1 out of 3 people in the United States will develop shingles during their lifetime.  The presence of a few skin lesions outside the primary or adjacent dermatomes is neither unusual nor of prognostic importance in immunocompetent patients. Simultaneous involvement of multiple non-contiguous dermatomes is very rare in immunocompetent patients, but overlapping in adjacent dermatomes occurs in 20%. About 1 - 4% of people with shingles are hospitalized for complications. Older adults and people with weakened or suppressed immune systems are more likely to be hospitalized. About 30% of people hospitalized for shingles have a weakened or suppressed immune system. *per 1,000 person-years. Image from: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5705a1.htm

5. Zoster and immunosuppression Incidence of zoster is higher in those receiving immunosuppressive therapy for autoimmune conditions: Biologics (TNF blockers), DMARDs, and Corticosteroids (2) Relative risk (RR) of 3.0 (95% CI: 1.1, 7.8) for herpes zoster during WGET treatment with etanercept (P=.03)

6. Should we think of Cancer? 590 residents of Rochester, Minnesota, for 9389 person-years after the diagnosis of herpes zoster. (3) (N Engl J Med. 1982; 307:393–7.) The overall relative risk was 1.1 (95 per cent confidence interval, 0.9 to 1.3). Slightly elevated relative risks for specific cancer sites only for colon and bladder tumors in women Patients with disseminated, recurrent, or gangrenous zoster, with post-herpetic neuralgia, or with ophthalmic zoster were not at elevated risk for subsequent cancer Screening for cancers in zoster is not recommended

7. What is my risk of VZV meningitis and should I have an LP?

8. Should I receive antivirals? Therapy for herpes zoster should accelerate healing, limit the severity and duration of acute and chronic pain, and reduce complications. Treatment should be targeted for: Immunocompromised patients, to reduce the risk of dissemination of VZV Persons at highest risk for complications are elderly persons, those with herpes zoster ophthalmicus , and immunocompromised patients. Older age, a greater degree of skin-surface area involved, and more severe pain at presentation are all predictors of persistent pain (post-herpetic neuralgia). All patients with acute herpes zoster ophthalmicus should receive antiviral therapy with the goal of preventing ocular complications. Some physicians still consider antiviral therapy to be optional for younger patients with uncomplicated shingles, although therapy has minimal risk and is potentially beneficial.

9. VACCINATE

10. References http://www.medscape.com/viewarticle/822982 CDC Expert Series on Zoster – MedSCape http://ofid.oxfordjournals.org/content/2/suppl_1/1203.extract# Open Oxford journals http://www.nejm.org/doi/10.1056/NEJM198208123070701 Cancer risk in Zoster http://www.cdc.gov/vaccines/pubs/pinkbook/varicella.html CDC Pink Book http://www.cdc.gov/shingles/hcp/clinical-overview.html CDC Zoster for Healthcare Professionals http://www.who.int/immunization/sage/meetings/2014/april/2_Background_document_Herpes_Zoster.pdf WHO Background document on Zoster http://www.jwatch.org/jw200711150000001/2007/11/15/what-incidence-shingles NEJM Incidence of Shingles http://www.medscape.com/medline/abstract/23036671 MedLine Abstract Risks for Shingles http://www.medscape.com/medline/abstract/15897984 Incidence of herpes zoster, before and after varicella-vaccination-associated decreases in the incidence of varicella, 1992-2002. J Infect Dis. 2005; 191(12):2002-7 (ISSN: 0022-1899) http://www.medscape.com/medline/abstract/24297190 Examination of links between herpes zoster incidence and childhood varicella vaccination. Ann Intern Med. 2013; 159(11):739-45 (ISSN: 1539-3704) https://www.ncbi.nlm.nih.gov/pubmed/16378799 Zoster in immunocompromised patients