Written by Jonathan Brewer
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Point-of-care ultrasound (POCUS) should be utilized in conjunction with the history and physical exam for the differentiation of cellulitis versus abscess.
Scan before you slice
This clinical review evaluated the utility of POCUS in differentiating soft tissue abscesses from cellulitis in the emergency department. Four meta-analyses were included, encompassing over 4,000 patients. Pooled sensitivity and specificity of POCUS ranged from 90-97% and 80-85% respectively, with one large meta-analysis demonstrating a positive likelihood ratio (LR+) of 6.5 and negative likelihood ratio (LR-) of 0.06. In pediatric populations in particular, POCUS sensitivity was 90-94%, with a specificity 80-83%. Utilizing POCUS even led to a correct change in management in many cases, with a number needed to treat (NNT) of 10. There were some limitations across these studies, including heterogeneity and variable operator skill. That being said, POCUS offers significant diagnostic value, especially when clinical findings are equivocal, and can safely guide management decisions such as the need for incision and drainage (I&D).
How does this change my practice?
This paper confirms my practice of utilizing POCUS to reliably differentiate cellulitis versus abscess (in conjunction with a history and physical). While it can help guide management in terms of confirming the need to perform an I&D, I would argue that it also assists in preventing unnecessary procedures by differentiating soft tissue structures such as a pseudoaneurysm or lymph node. I personally am looking forward to the future integration with artificial intelligence for soft tissue interpretation, but that’s another study for another day.
Source
What is the Utility of Point-of-Care Ultrasound for Diagnosis of Soft Tissue Abscess vs. Cellulitis? J Emerg Med. 2025 May;72:121-128. doi: 10.1016/j.jemermed.2024.11.012. Epub 2024 Nov 26. PMID: 40274497
