An Uncommon Effect-Children Who Develop Herpes Zoster at Varicella Vaccination Site

Decades ago, contracting varicella—or chicken pox—was almost a given; rare was the child who made it through his or her formative years without coming down with the virus. The varicella vaccine, first available in 1995, has eliminated that rite of passage for most. While it’s no doubt a relief to sidestep this itchy scourge, the varicella virus introduced into the body via vaccine remains latent and can reactive decades later in the form of herpes zoster, otherwise known as shingles. Herpes zoster is mainly a disease of older adults, but a group of scientists has discovered that a small percentage of children respond to the varicella vaccine by developing herpes zoster at or near the vaccine site.

The team, comprised of researchers at Harvard Medical School and Boston Children’s Hospital, issued a case report in a recent issue of the journal Pediatric Dermatology. They described 7 children between the ages of 1.5 and 6-years-old who presented with herpes zoster at or very close to the site of their varicella vaccination. Herpes zoster appeared anywhere from 6 months to 30 months after the varicella vaccine was administered. Six out of the 7 suffered from symptoms such as itchy and painful lesions and fever. One child, the youngest, had no systemic symptoms. In 5 of the children, there were no factors that would suggest a reason for the herpes to suddenly occur. In 1 child, the herpes showed up after the child got an influenza shot; in another child, the rash occurred after surgery. Five of the children were treated with a course of acyclovir, lasting anywhere from 5 to 14 days.

Research has found that children who develop herpes zoster after receiving the varicella vaccine are likely to have the location of the herpes correspond to the location of the vaccine. This may be because the vaccine introduces a high concentration of the virus into the body in one small spot, priming it to reactivate at a later time.

Fortunately, when herpes zoster occurs in children, it seems to be less virulent than when it occurs in adults. The researchers noted in their report that the children presented with “small pink to erythematous papules or pseudovesicles, rather than true vesicles.” Pain and fever didn’t seem to play a starring role, nor did postherpetic neuralgia, which is a burning sensation that’s often a complication of herpes zoster. “Herpes zoster in otherwise healthy children is associated with a mild course and complete recovery, and our 7 patients recovered without complications,” they wrote.

Because the presentation of herpes zoster in children—especially children who’ve received the varicella vaccine—may be different from the typical herpes presentation, the scientists stressed that a proper diagnosis is important. The condition may be misdiagnosed as eczema or contact dermatitis even though those maladies typically involve intense itching and more severe skin changes than might be observed. If a clinician is unable to make a diagnosis of herpes zoster based on signs and symptoms, laboratory testing may be the next step.

According to the researchers, although the use of the varicella vaccine has reduced the number of cases of chicken pox in this country, the incidence of herpes zoster has remained fairly steady, ranging from 21 to 28 per 100,000 person-years before the vaccine was introduced, to 27.4 to 93.3 per 100,000 person-years since the vaccine has been in wide use.

Laurie Saloman, MS, is a health writer with more than 20 years of experience working for both consumer- and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.