Complications and associated factors among children hospitalized with varicella in Iran: a retrospective cohort study

Varicella is usually self-limiting in children, but hospitalized cases may develop serious cutaneous, neurological, hematological, cardiopulmonary, and hepatic complications. This study aimed to determine the frequency and pattern of varicella-associated complications and identify factors associated with complicated disease among hospitalized children. This retrospective cohort study included children aged 1 month to 18 years admitted with clinically diagnosed varicella to Imam Ali Hospital, Karaj, Iran, between June 2022 and June 2025. Demographic characteristics, underlying conditions, corticosteroid exposure, previous hospitalization, complication categories, intensive care unit admission, mortality, and length of stay were extracted from medical records. Associations were examined using chi-square or Fisher’s exact tests, the Mann–Whitney U test, and binary logistic regression. Odds ratios were reported with 95% confidence intervals. A total of 133 children were included. At least one complication was documented in 55.6% of patients (95% CI, 47.2%–63.8%). Cutaneous complications were most frequent (27.1%), followed by gastrointestinal or hepatic (21.1%), neurological (9.8%), and hematological or vascular complications (8.3%). Intensive care was required in 12.0% (95% CI, 7.5%–18.6%), and in-hospital mortality was 2.3% (95% CI, 0.8%–6.4%). Median hospital stay was longer in patients with complications than in those without complications (6 vs. 3 days; Mann–Whitney U = 1139.5; p < 0.001). No baseline factor showed a consistent independent association with overall complications. Children with complications had higher adjusted odds of intensive care admission, although the association was not statistically significant (adjusted OR, 3.06; 95% CI, 0.78–12.04; p = 0.108). Among children hospitalized with varicella at this referral center, complications were frequently documented and were associated with longer hospitalization. Cutaneous and gastrointestinal or hepatic complications were the most commonly recorded categories. These findings should be interpreted within the context of a single-center hospitalized population and warrant confirmation in larger multicenter studies. Not applicable. This study was a retrospective observational study and did not involve assignment of participants to an intervention. Complications occurred in 55.6% of children hospitalized with varicella. Cutaneous complications were the most frequent, affecting 27.1% of patients. Complicated varicella doubled the median hospital stay from 3 to 6 days. 12% of patients required intensive care, and 2.3% died. No baseline characteristic consistently predicted overall complications.