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

BACKGROUND Functional infrared imaging (fIRI) is used to provide information on circulation, thermal properties and thermoregulatory function of the cutaneous tissue in several clinical settings. OBJECTIVES This 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). METHODS 10 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. RESULTS Higher 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. CONCLUSIONS fIRI 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.