Image-Based Machine Learning Shows Promise in Diagnosing Cellulitis

Cellulitis is one of the most common skin infections seen in emergency departments and inpatient wards, yet it remains one of the most frequently misdiagnosed conditions in medicine. A new research letter published in the Archives of Dermatological Research by a team at The Ohio State University Wexner Medical Center suggests that an accessible image-based machine learning tool could help clinicians distinguish true lower extremity cellulitis from its many mimickers, a distinction that carries enormous consequences for patients and health systems alike.

The stakes of getting this diagnosis right are remarkably high. When cellulitis is mistakenly diagnosed in patients who actually have pseudocellulitis conditions such as venous stasis dermatitis, lipodermatosclerosis, or inflammatory reactions to other causes, those patients are often admitted unnecessarily and treated with days of intravenous antibiotics they do not need. Landmark research published in JAMA Dermatology estimated the annual cost of misdiagnosed lower extremity cellulitis in the United States at tens of millions of dollars, alongside avoidable hospital-acquired complications and delays in treating the actual underlying disease. Conversely, missing genuine cellulitis can allow a rapidly spreading bacterial infection to progress toward sepsis, making accurate and timely differentiation a genuine clinical imperative.

Traditional approaches to this diagnostic dilemma have relied on clinical prediction rules, such as the ALT-70 model and the Dundee score, which incorporate features like asymmetry of the leg, temperature, leukocyte counts, and tachycardia to improve diagnostic accuracy. While these models have shown promise in validation studies, their adoption has been limited by the need for laboratory values and bedside calculations, and their performance in real-world settings remains variable. The Ohio State team, led by first author Priya Gupta and corresponding author Abraham M. Korman, took a fundamentally different approach by asking whether the visual appearance of the affected skin itself contains enough diagnostic signal to be captured by a machine learning classifier.

What makes this study particularly notable is the tool the researchers chose. Rather than training a bespoke deep learning network from scratch, which typically requires substantial computing infrastructure and machine learning expertise, the team used Google’s Teachable Machine, a freely available web-based platform designed to let non-specialists build image classifiers with remarkably little technical overhead. Teachable Machine applies transfer learning, taking a neural network pre-trained on millions of general images and fine-tuning its final layers on a small set of custom examples. This approach drastically reduces the data requirements, allowing a clinically driven research team to develop a working classifier in a fraction of the time and cost associated with conventional model development.

The researchers assembled image datasets from two complementary sources: publicly available clinical photographs published in peer-reviewed manuscripts and inpatient images obtained at The Ohio State University under Institutional Review Board protocol 2023H0077, approved in March 2023, with written informed consent from all patients for the use of identifiable images. Published images were de-identified and therefore did not require additional review. This dual-source strategy balanced the reproducibility of textbook-quality published photographs against the messier but more clinically realistic appearance of cellulitis on hospital wards, where bandages, leg elevation, lighting variation, and concurrent edema complicate the visual picture.

The model’s performance was evaluated using standard statistical measures that readers of the machine learning literature will recognize. The area under the receiver operating characteristic curve, or AUROC, summarizes a classifier’s ability to discriminate between classes across all decision thresholds, with values approaching 1.0 indicating near-perfect separation and 0.5 representing chance-level guessing. The team also reported confidence intervals to quantify uncertainty around their estimates and Cohen’s kappa, a statistic that measures agreement beyond what would be expected by chance and is particularly valued in diagnostic studies because it corrects for the inflation that arises when a condition is common.

The work builds directly on a growing program of research by overlapping members of the same group. In a 2026 study published in the International Journal of Dermatology, Fosu and colleagues, including several of the cellulitis study’s co-authors, demonstrated that Google’s Teachable Machine could identify validated cases of pyoderma gangrenosum, an ulcerative skin disorder that is notoriously difficult to distinguish from other wound types. That earlier result provided proof of concept that the platform could capture the subtle morphological signatures of inflammatory dermatoses, and the cellulitis study extends the paradigm to one of the highest-volume and most consequential diagnostic challenges in acute care medicine.

The clinical vision behind this line of work is augmentation rather than replacement. Emergency physicians, hospitalists, and even primary care providers see few cases of confirmed cellulitis relative to dermatology specialists, and interobserver agreement on the diagnosis is historically modest. A point-of-care image classifier could function as a second opinion, flagging cases whose appearance deviates from typical cellulitis and prompting consideration of pseudocellulitis diagnoses before empiric antibiotics and hospital admission are initiated. In telemedicine contexts, where the examination is already mediated by photographs, such a tool could integrate naturally into existing workflows.

Important limitations temper the enthusiasm. The datasets analyzed in the study are not publicly available due to patient privacy and institutional restrictions, though they are available from the corresponding author on reasonable request. Models trained on photographs from a single academic center and published literature may struggle to generalize across skin tones, imaging devices, and clinical environments, a persistent challenge in dermatology-focused artificial intelligence. The authors also disclose that the machine learning tool was used to create and test the classifier itself, with the team reviewing and editing all outputs and taking full responsibility for the published content, an increasingly common transparency practice in AI-assisted research. Prospective validation in diverse, real-world emergency and inpatient settings will be essential before such a tool can influence bedside decisions.

Even with those caveats, the study represents a compelling demonstration of how democratized machine learning platforms can move from novelty to clinical relevance. The project was supported by the Samuel J. Roessler Memorial Medical Student Research Scholarship, underscoring that meaningful contributions to diagnostic artificial intelligence no longer require industrial-scale resources. As image-classification tools of this kind accumulate validated use cases across dermatology, from ulcerative disorders to soft tissue infections, the prospect of inexpensive, rapidly deployable diagnostic adjuncts for some of medicine’s most error-prone judgment calls is moving steadily closer to practice.

Subject of Research: Machine learning-based image classification for the diagnosis of lower extremity cellulitis

Article Title: Augmenting the diagnosis of cellulitis using image-based machine learning

Article References: Gupta, P., Fosu, N. A., Bittinger, Z., Bobulsky, G. S., Conroy, M., Eisinger, G. J., Kaffenberger, B. H., Kirven, R. M., & Korman, A. M. (2026). Augmenting the diagnosis of cellulitis using image-based machine learning. Archives of Dermatological Research, 318(1), Article 469. https://doi.org/10.1007/s00403-026-04964-2

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04964-2

Keywords: cellulitis, machine learning, teachable machine, dermatology, misdiagnosis, pseudocellulitis, image classification, diagnostic support, emergency medicine, skin and soft tissue infection, transfer learning, predictive medicine