The ALT-70 cellulitis model maintains predictive value at 24 and 48 hours after presentation.

BACKGROUND: Cellulitis has many potential mimickers, and its misdiagnosis often leads to unnecessary hospitalizations and higher health care costs. The ALT-70 predictive model offers an objective tool to help differentiate between cellulitis and other clinically similar conditions at the time of initial emergency department (ED) presentation. OBJECTIVE: To evaluate the performance of the ALT-70 predictive model at 24 and 48 hours following ED presentation. METHODS: We performed a retrospective review of our prior cohort and expanded our data collection to include data at 24 and 48 hours after initial ED presentation. We compared classification measures for the ALT-70 at the time of initial ED presentation, 24 hours after presentation, and 48 hours after presentation. RESULTS: There was a statistically significant difference in median ALT-70 score between patients with true cellulitis and those with mimickers of cellulitis at all time points. Sensitivity, specificity, positive predictive value, and negative predictive value of the ALT-70 score was similar across all 3 time points. LIMITATIONS: Single-center design may reduce generalizability. CONCLUSION: At 24 and 48 hours, the ALT-70 performed similarly to the way it performed at the time of initial ED presentation, allowing for its use in a wider array of clinical settings.

Costs and Consequences Associated With Misdiagnosed Lower Extremity Cellulitis.

IMPORTANCE: Inflammatory dermatoses of the lower extremity are often misdiagnosed as cellulitis (aka "pseudocellulitis") and treated with antibiotics and/or hospitalization. There is limited data on the cost and complications from misdiagnosed cellulitis. OBJECTIVE: To characterize the national health care burden of misdiagnosed cellulitis in patients admitted for treatment of lower extremity cellulitis. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study using patients admitted from the emergency department (ED) of a large urban hospital with a diagnosis of lower extremity cellulitis between June 2010 and December 2012. Patients who were discharged with a diagnosis of cellulitis were categorized as having cellulitis, while those who were given an alternative diagnosis during the hospital course, on discharge, or within 30 days of discharge were considered to have pseudocellulitis. A literature review was conducted for calculation of large-scale costs and complication rates. We obtained national cost figures from the Medical Expenditure Panel Survey (MEPS), provided by the Agency for Healthcare Research and Quality (AHRQ) for 2010 to calculate the hospitalization costs per year attributed to misdiagnosed lower extremity pseudocellulitis. EXPOSURES: The exposed group was composed of patients who presented to and were admitted from the ED with a diagnosis of lower extremity cellulitis. MAIN OUTCOMES AND MEASURES: Patient characteristics, hospital course, and complications during and after hospitalization were reviewed for each patient, and estimates of annual costs of misdiagnosed cellulitis in the United States. RESULTS: Of 259 patients, 79 (30.5%) were misdiagnosed with cellulitis, and 52 of these misdiagnosed patients were admitted primarily for the treatment of cellulitis. Forty-four of the 52 (84.6%) did not require hospitalization based on ultimate diagnosis, and 48 (92.3%) received unnecessary antibiotics. We estimate cellulitis misdiagnosis leads to 50 000 to 130 000 unnecessary hospitalizations and $195 million to $515 million in avoidable health care spending. Unnecessary antibiotics and hospitalization for misdiagnosed cellulitis are projected to cause more than 9000 nosocomial infections, 1000 to 5000 Clostridium difficile infections, and 2 to 6 cases of anaphylaxis annually. CONCLUSIONS AND RELEVANCE: Misdiagnosis of lower extremity cellulitis is common and may lead to unnecessary patient morbidity and considerable health care spending.