WEDNESDAY, March 27, 2024 -- Skin surface temperature measures differ between cases of cellulitis and pseudocellulitis, according to a study published online March 27 in JAMA Dermatology.

Michael S. Pulia, M.D., Ph.D., from the University of Wisconsin-Madison School of Medicine and Public Health, and colleagues validated the differences in skin surface temperatures between patients with cellulitis and those with pseudocellulitis in a prospective diagnostic validation study conducted among patients presenting to the emergency department with acute dermatologic lower-extremity symptoms. The final sample included 204 patients, 92 of whom had a consensus diagnosis of cellulitis.

The researchers found that all skin surface temperature measures (mean temperature, maximum temperature, and gradients) differed significantly between cellulitis and pseudocellulitis. The maximum temperature of the affected limb was 33.2 and 31.2 degrees Celsius for those with cellulitis and pseudocellulitis, respectively. The optimal temperature measure was the maximal temperature, with a cut point of 31.2 degrees Celsius in the affected skin, yielding a mean negative predictive value of 93.5 percent and a sensitivity of 96.8 percent. For all three measures, the sensitivity remained above 90 percent, while there was considerable variation seen in specificity (asymmetry, leukocytosis, tachycardia, and age 70 years or older prediction model; maximum temperature of the affected limb; and combination measure: 22.0, 38.4, and 53.9 percent, respectively).

"Surface thermal imaging may represent a useful adjunct to the clinical assessment of cellulitis (reducing overdiagnosis), but additional validation of diagnostic performance and cutoff values in more diverse populations is needed," the authors write.