Chickenpox complications among immunocompetent hospitalized children in Italy. Acyclovir-Chickenpox Italian Study Group.

OBJECTIVE: To evaluate the frequency and clinical spectrum of chickenpox complications among immunocompetent hospitalized children.

PATIENTS AND METHODS: Multicentre retrospective study of clinical records of all patients consecutively hospitalized for varicella during the last decade, in ten tertiary care clinical centres of Pediatrics and Infectious Diseases, throughout Italy.

RESULTS: Two hundred and nineteen out of 991 patients (22.1%) hospitalized for varicella suffered from a complicated disease (247 complicating events on the whole). Central nervous system (CNS) involvement was prevalent (104 episodes), followed by skin/soft tissue infections, lower respiratory tract involvement, and thrombocytopenia. A complicated disease was significantly associated with the male gender and an elevated incidence of varicella-zoster (VZ) virus infection acquired by household contacts. The involvement of lower respiratory airways and skin/soft tissues seemed to occur at an earlier age, compared with CNS and thrombocytopenia. Moreover, lower respiratory tract and skin/soft tissue infections occurred earlier during disease course than complications interesting the CNS and coagulation system. All subjects with complicated chickenpox showed a favourable outcome within 5-40 days, except two patients developing a lethal cardiomyopathy and Reye syndrome, respectively. Anyway, chickenpox complications led to a prolonged hospitalization, and needed further pharmacologic treatment in all evaluated cases. The administration of anti-VZ virus treatments (i.v. acyclovir or VZ immunoglobulins) did not modify significantly the course of disease in treated patients, when compared with untreated ones.

CONCLUSIONS: Although chickenpox is considered a self-limiting, uncomplicated disease in immunocompetent children, when assessing hospitalized patients a considerable incidence and a broad spectrum of complications are observed, requiring prolonged admission and pharmacologic and supportive care. Even though a lethal outcome remains a rare occurrence, it may be of relevant concern when considering the overall incidence of chickenpox in the general population. The role of an early antiviral treatment in reducing the incidence and severity of varicella complications deserves further evaluation.