Satellite lesions accompanying herpes zoster a new prognostic sign for high-risk zoster

Summary Background The incidence, clinical relevance and pathogenesis of single, isolated, varicella-like skin lesions occurring far beyond the primary herpes zoster (HZ)-affected dermatome remain unclear. Objectives To search prospectively for these satellite lesions in 120 patients with HZ and to correlate their presence with a series of clinical, histological and virological data. Methods Relevant clinical data were recorded from 109 patients with proven HZ using immunohistochemistry on Tzanck smears. Furthermore, skin biopsies and blood samples were obtained from a subgroup of patients presenting with primary HZ with and without satellite lesions for histology, immunohistology, serology and real-time polymerase chain reaction. Results This study identified satellite lesions in 21·1% of the patients with HZ. Their presence conveyed a statistically significant relative risk (RR) for severe (RR 3·27, P < 0·001), multidermatomal (RR 10·6, P < 0·001) and multistage HZ (RR 3·30, P < 0·001); systemic signs (RR 2·08, P = 0·0031); immunosuppression (RR 2·38, P = 0·0014) and hospitalization (RR 2·94, P < 0·001). Varicella zoster virus (VZV) viraemia was higher (mean 4075 copies mL−1) in patients with HZ with satellite lesions than in those without (mean 1466 copies mL−1). In contrast to HZ lesions, satellite lesions often presented positive VZV immunostaining in endothelial cells, suggesting a similar pathogenesis to varicella. A limitation of this study is the centre-linked overrepresentation of immunocompromised patients. Conclusions Total-body examination searching for satellite lesions is a rapid, simple and reliable tool for identifying patients with high-risk HZ.