Case Presentation: A healthy 3-year-old boy presented with 5 days of a scaly and crusting rash on the left side of his face that began as a few bumps on his left forehead (Image 1). He had no history of chickenpox, is up to date on immunizations including varicella, and has no family history of immunodeficiency. On exam, he had a papular rash with crusting over the V1 distribution with left eyelid swelling. Labs showed white blood cell count of 5.9, platelets of 274,000 and hemoglobin of 12.3; his complete metabolic panel was unrevealing. He was evaluated by dermatology and ophthalmology who agreed with the diagnosis of herpes zoster ophthalmicus (HZO). Woods lamp with fluorescein did not reveal vesicular lesions in his eyes. He was treated with intravenous acyclovir for 1.5 days and then switched to oral acyclovir to complete a 7-day course (Image 2). He was referred to Allergy and Immunology for outpatient workup of a possible immunodeficiency and his workup was unremarkable and revealed no underlying immune process.
Discussion: HZO results from reactivation of latent virus in the dorsal root ganglia of the ophthalmic division of the trigeminal nerve. While Herpes zoster (HZ) reactivation is common in adults, it is exceedingly rare in pediatric patients. This patient presented with HZO without known exposure to or prior history of chickenpox, though he has received the live-attenuated varicella vaccine. The literature lacks reports of HZO, both with and without ocular involvement, in pediatric patients due to the rarity of the condition in this population.1,2,3,5,6 Previous case reports demonstrate herpes zoster infections in otherwise healthy children at very low rates, with an estimated of risk of approximately 0.45/100,000 person-years and even lower rates for HZO4. Literature suggests HZ infections after varicella vaccination generally occur within months to a few years for immunocompetent children due to reactivation of the vaccine or wild-type strain of varicella.7 Studies aiming to characterize incidence rates of HZ infections after varicella vaccination are sparse, but one population-based study showed that childhood varicella vaccination reduced HZ risk, with a higher incidence of wild-type than vaccine-strain.8 Studies of HZ in immunocompromised hosts highlight the importance and relevance of underlying cellular immunity and other factors, which warrant further investigation.9,10 Children with HZO have an overall favorable outcome, though complications including ocular involvement, uveitis, and strokes have been reported in rare cases.3
Conclusions: We present an interesting case of a young child with a left-sided facial dermatomal rash consistent with HZO in the setting of prior varicella vaccination. Further research is required to understand possible underlying processes predisposing healthy children with no known herpes infections to develop reactivation of HZ and symptomatic HZ infections.