PA34 A case of disseminated herpes zoster in an immunocompetent child

Abstract

Herpes zoster (HZ) caused by the reactivation of varicella-zoster virus (VZV) affects mainly the adult population. The incidence is low in children (0.45 cases per 1000 individuals annually), especially in the immunocompetent. It is said to be disseminated when there are > 20 lesions outside the primary and adjacent affected dermatome. We present this case to highlight a rare complication of cutaneous dissemination in a previously healthy child with HZ, following in utero exposure to varicella at 28 weeks’ gestation. A 15-year-old boy presented with painful blisters in the T2 dermatome of 1 week’s duration, which later spread to trunk, extremities and face. This was associated with fever and neuralgia. There was no previous history of varicella and no recent contact history. He had no significant past medical history and was not on any medications. Antenatal history revealed that his mother had varicella at 28 weeks’ gestation and was treated with aciclovir. He was febrile on admission (39°C). There were coalesced vesiculopustules and crusted lesions with marked perilesional erythema in the T2 dermatome. In addition, disseminated vesicular lesions were seen on the trunk, extremities and face. Remaining systemic examination was unremarkable. C-reactive protein was elevated. Complete blood count and renal function tests were normal. Liver function tests, namely alanine transaminase and γ-­glutamyl transferase were elevated. Blood culture showed no growth. Varicella-zoster IgG was positive. Viral swab (polymerase chain reaction) from the skin lesions was positive for varicella-zoster DNA. Infectious serology for HIV, hepatitis B and hepatitis C was negative. Antinuclear antibody and antineutrophil cytoplasmic antibodies were negative. A clinical diagnosis of HZ with cutaneous dissemination was made, and he was treated with intravenous aciclovir. Intravenous antibiotics were added for suspected secondary bacterial infection. Disseminated zoster is less common in children and mainly occurs in patients with underlying immunodeficiency like HIV, immunosuppressive drug use or malignancy. In immunocompetent children, this can happen when primary infection (varicella) has occurred in utero or the first year of life due to the low response in specific varicella-zoster virus immunity. Complications like cutaneous dissemination due to viraemia are rare in healthy children, but can affect 2–10% of immunocompromised patients. It occurs 3–4 days after the onset of dermatomal lesions. It is important to look for other complications, especially in the immunocompromised, as viraemia can affect the brain, kidneys, lung and liver. Sequelae like postherpetic neuralgia is rare, but it is important to follow-up these children to look for its development.