Joint functional impairment and thermal alterations in patients with Psoriatic Arthritis: A thermal imaging study

• Functional infrared imaging (fIRI) is a non invasive technique providing a dynamical and functional evaluation of cutaneous thermal properties in several clinical settings.
• An altered functional response due to an isometric exercise plays an important role to evaluate the increase of cutaneous circulation in the presence of inflammatory disease like PsA
• We have demonstrated the feasibility of fIRI as new imaging technique for the detection of peripheral PsA, evaluating different temperatures between PsA patients and a control group after a functional exercise.
• fIRI outcome correlated with the presence of active inflammation assessed through PWD-US technique in the considered ROI.

BackgroundFunctional infrared imaging (fIRI) is used to provide information on circulation, thermal properties and thermoregulatory function of the cutaneous tissue in several clinical settings.ObjectivesThis study aims to evaluate the application of fIRI in Psoriatic Arthritis (PsA) assessment, evaluating the thermoregulatory alterations due to joint inflammation in PsA patients both in basal conditions and after a mild functional (isometric) exercise; fIRI outcomes were compared with those provided by Power Doppler Ultrasonography (PWD-US).Methods10 patients with PsA and 11 healthy controls were enrolled in the study. The cutaneous temperature dynamics of 20 regions of interest located on the dominant hand were recorded by means of high-resolution thermal imaging at baseline and after a functional exercise.ResultsHigher temperature values and faster temperature variations characterized the PsA group compared to healthy controls, confirming that the PsA-related inflammatory state alters the normal thermal proprieties of the skin overlying inflamed joints. fIRI outcomes correlated with the PWD-US findings.ConclusionsfIRI applied to the study of the response to a functional stimulus may represent an innovative, non-invasive, and operator-independent method for the assessment of peripheral PsA.