Utility of Thermal Imaging in Diagnosis of Cellulitis for Lower Extremity Complaints in the Emergency Department

The overall purpose of the study is to determine how providing physicians with a quantitative measure of skin surface temperature influences diagnoses and diagnostic confidence in potential cellulitis cases when added to the standard evaluation.

Study Overview

• Status: Completed
• Conditions: Cellulitis; Skin and Subcutaneous Tissue Infection
• Intervention / Treatment: Diagnostic test: Thermal Imaging as Diagnostic Adjunct

Detailed Description

Previous literature estimates the emergency department misdiagnosis rate for cellulitis exceeds 30% due to conditions which can mimic cellulitis (termed pseudocellulitis). These diagnostic errors are associated with an estimated $195 to $515 million dollars in avoidable healthcare spending each year. Objective skin surface temperature measurement, obtained via thermal imaging cameras, has been proposed as a diagnostic adjunct that may reduce diagnostic error in cases of suspected cellulitis. One recent study, identified that the maximum affected skin temperature in cellulitis is significantly higher than in pseudocellulitis, and the temperature gradient between affected and unaffected sites in patients with cellulitis is significantly higher than in patients with pseudocellulitis.

The overall purpose of the study is to determine how providing physicians with a quantifiable measure of skin surface temperature information influences diagnoses and diagnostic confidence in potential cellulitis cases when added to standard physical exam techniques

The Aims of the study are to :

Specific Aim 1: To characterize the temperature difference between affected and unaffected limbs in patients with cellulitis in the emergency department.

Specific Aim 2: To characterize the temperature difference between cases of cellulitis and pseudocellulitis

Specific Aim 3: To determine how quantifying temperature gradients changes diagnostic confidence and accuracy when added to the standard diagnostic evaluation for potential cellulitis.

The investigators will prospectively enroll a maximum of 560 patients with non-traumatic lower extremity dermatologic complaints with visible erythema (potential cellulitis) in the University of Wisconsin Emergency Department. A thermal image and a photograph of the affected and the unaffected limbs will be taken.

• Study Type: Observational
• Enrollment (Actual): 416

Contacts and Locations

• Study Contact: Name: Rebecca J Schwei, MPH; Phone Number: (608) 262-2908; Email: rschwei@medicine.wisc.edu

Study Locations

• United States
  • Wisconsin
    • Madison, Wisconsin, United States, 53705
      • University of Wisconsin Emergency Department

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Seeking to include all patients who present to the Emergency Department for a skin related, acute lower extremity complaint and able to provide informed consent.

Description

Inclusion Criteria:

• Participant is presenting to the University of Wisconsin Emergency Department
• Participant has an acute skin complaint on the lower extremity

Exclusion Criteria:

• Participant is has limited English and Spanish proficiency
• There was an acute traumatic injury of affected area in last 5 days- includes burns
• Affected area has a confirmed fracture
• Participant is pregnant
• Participant is a prisoner
• Current complaint is in an area of past surgical procedure (within past 4 weeks)
• Participant has implant or hardware at site
• Animal or human bite is cause of complaint
• Temperature of the leg has been altered in the last one hour
• Unable to provide informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
All Participants; All participants will have thermal imaging of their lower extremities. The temperature values will be shared with the attending physician. The physician will be asked questions about their diagnostic confidence before and after seeing the temperature values.	Diagnostic test: Thermal Imaging as Diagnostic Adjunct; Thermal images of the participants lower extremities will be taken and skin surface temperature values will be provided to the healthcare provider for review during the emergency department encounter.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Skin Temperature Difference Between Affected and Unaffected Legs for Participants with Cellulitis	Differences in skin surface temperatures of affected and unaffected areas for those with a final diagnosis of cellulitis.	up to one hour
Skin Temperature Difference Between Participants Diagnosed with Pseudocellulitis and Cellulitis	Determine differences in skin surface temperatures between cases of pseudocellulitis and cellulitis (on the affected legs).	up to one hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Diagnostic Confidence as Measured by Physician Self-Report	Comparison of the change in diagnostic confidence as measured by the attending physician response pre/post thermal imaging review. This was a question developed by the study team and response options include not at all confident, slightly confident, somewhat confident, very confident, extremely confident. No number values are assigned to response values as of yet.	up to one hour
Diagnostic agreement with expert review panel	Provider cellulitis diagnostic assignment (yes/no) will be compared to an expert panel to determine the rate of concordance.	6 months

Collaborators and Investigators

• Sponsor: University of Wisconsin, Madison
• Collaborators: Agency for Healthcare Research and Quality (AHRQ)
• Investigators: Principal Investigator: Michael Pulia, MD, MS, University of Wisconsin, Madison

Study record dates

Study Major Dates

• Study Start (Actual): July 18, 2021
• Primary Completion (Actual): January 18, 2023
• Study Completion (Actual): February 18, 2023

Study Registration Dates

• First Submitted: June 9, 2021
• First Submitted That Met QC Criteria: June 9, 2021
• First Posted (Actual): June 16, 2021

Study Record Updates

• Last Update Posted (Estimated): December 7, 2023
• Last Update Submitted That Met QC Criteria: December 5, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Keywords: Diagnostic accuracy; Diagnostic confidence; Diagnostic error
• Additional Relevant MeSH Terms: Pathologic Processes; Infections; Inflammation; Disease Attributes; Connective Tissue Diseases; Skin Diseases, Infectious; Suppuration; Emergencies; Cellulitis
• Other Study ID Numbers: 2018-0823 Phase 2; A534100 (Other Identifier: UW Madison); SMPH/EMERG MED (Other Identifier: UW Madison); 1K08HS024342-01A1 (U.S. AHRQ Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No