Infrared thermography of the tongue in systemic lupus erythematosus: a pilot study of thermal response to cold stimulation.

Systemic lupus erythematosus is a chronic autoimmune disease in which vascular and microcirculatory disorders can play a significant role in the clinical picture. The aim of this pilot study was to evaluate the dynamic thermal response of the tongue to a controlled cooling stimulus in patients, compared with that of healthy individuals. This observational study was conducted in 106 healthy individuals and 10 patients. Measurements were taken using a thermal imaging camera. After the baseline measurement, participants held cold water in their mouths for 60 s. Thermal images of the tongue were recorded immediately after the stimulus and after 2, 5, and 10 min. Mean temperature was analysed. Differences between groups were assessed using the Mann-Whitney U test. No significant differences were found between groups in most absolute temperature values. In the unadjusted analysis, at 2 min after stimulation, patients with systemic lupus erythematosus had significantly higher temperatures than healthy controls in the apex and central region of the tongue. Significant differences were also observed at 10 min in the apex and central region. The most consistent between-group differences were observed in dynamic recovery parameters. The T2-T0 parameter differed significantly between groups in all analysed tongue regions. In the central region, additional significant differences were observed for T0-T, T5-T0, and T10-T0. After false discovery rate adjustment, significant differences remained for T2-T0 and T10-T0 in the central region of the tongue. Overall, patients with SLE demonstrated a tendency toward greater post-cooling temperature recovery, particularly in the central region and apex of the tongue. Dynamic thermography of the tongue following controlled cold stimulation may reveal differences in thermal response between SLE patients and healthy individuals that are not apparent from baseline temperature alone. Due to the pilot nature of the study, the results should be considered preliminary and require confirmation in larger, well-characterised cohorts.