Children Treated for Slow-flow Vascular Malformations: Overall Description and Focus on Complications Such as Cellulitis.

Some patients with slow-flow vascular malformations (SFVMs) develop recurring cellulitis. The main objective of this study was to describe SFVMs in children. Other objectives were to determine the frequency of cellulitis episodes, and the factors associated with the occurrence of cellulitis. This retrospective, longitudinal, single-centre study included all children with SFVMs being managed at Lille University Hospital between 1994 and 2020. Data were collected using a standardized questionnaire. After a descriptive analysis, the variables associated with the onset of cellulitis were analysed; 133 patients (median age at diagnosis: 72 months; 53% girls) were included. SFVMs were: venous (81%), lymphatic-venous (10%), capillary-venous (5%), and lymphatic (4%). Nine children had presented at least 1 episode of cellulitis (7%, 95% CI: 4-12) and 29 episodes were reported (median: 3, interquartile range: 2-4; median age at the first episode: 3.5 years). Cellulitis occurred more frequently in young children, with lymphatic and syndromic forms of SFVM, large SFVMs, affecting skin folds, and without long-term SFVM treatment. In conclusion, the occurrence of cellulitis in patients with a SFVM is rare. However, after the first episode, it frequently becomes recurrent, particularly in some patients with identified risk factors, who may require antibiotic prophylaxis.