Three Ds for diagnosing necrotizing fasciitis by front-line clinicians

Necrotizing fasciitis (NF) is a life-threatening infection and a surgical emergency. Not all clinicians have the experience or resources to detect NF in its early stages.

To develop a diagnostic algorithm for primary care and emergency physicians to identify patients with possible NF, including an initial approach to triaging such individuals.

Medline was searched to identify studies of validated algorithms for NF diagnosis and/or cohort or case series providing clinical and diagnostic features of NF. Candidate algorithms were validated via application to 3 published cases of initially misdiagnosed NF. We retrospectively reviewed NF cases between 2011 and 2022 at our center to validate our algorithm.

The search yielded 540 articles; 109 were included following a review of abstracts. No published validated diagnostic algorithm was identified. Using the reported clinical and diagnostic features of NF, we generated an algorithm of the "3Ds" of NF: Disproportionate pain, Dermatological findings, and Disorganized physiology. A larger number of Ds indicated a greater level of suspicion for NF and prioritization for urgent surgical consultation. In 3 published cases of missed NF, the 3Ds algorithm successfully identified all as having possible NF. On reviewing our cases, we identified 56 patients with NF during an 11 year period. 66% of whom had the 3Ds at their initial presentation.

The 3Ds algorithm, a simple and easy-to-remember tool can be easily applied in a primary or emergency care setting, and may improve the early diagnosis of NF. Retrospective analysis of NF cases allows for validation of this algorithm. However, this algorithm requires prospective validation.