Rate of concomitant cellulitis and osteoarticular infections in a pediatric population

Concern for infection is a common presentation in pediatric emergency departments. Clinical signs of cellulitis in pediatric patients often lead to a workup for osteoarticular infection despite a lack of evidence to suggest that the two entities commonly co-exist. With this in mind, we asked: (1) What is the rate of concomitant cellulitis and osteoarticular infections in the pediatric population? (2) What factors are associated with concomitant cellulitis and osteoarticular infections? This is a retrospective study of 482 pediatric patients who underwent MRI to evaluate for either cellulitis or an osteoarticular infection at a single tertiary care children's hospital. Data were analyzed to assess the prevalence of osteomyelitis concomitant with cellulitis in our sample population. Concomitant cellulitis and osteoarticular infection were present in 11% of all cases (53/482). Of the concomitant infections, 92% percent (49/53) were present in distal locations (Group 1) and 8% (4/53) were present in proximal locations (Group 2). Bivariate analysis showed that concomitant infections on the distal extremities were significantly more common than concomitant infections on the proximal extremities ( P  < 0.001). We found that concomitant cellulitis and osteoarticular infection were (1) uncommon and (2) significantly less common when clinical signs of cellulitis were present in the proximal extremities (proximal to ankle or wrist). This suggests that advanced imaging is most appropriate for patients who present with cellulitis on the distal extremities and can be used more judiciously in patients presenting with cellulitis on the proximal extremities. Level of Evidence - Level III.