Local thermal hyperemia (LTH) in the skin is a biphasic response to local heating involving both neurovascular and endothelial responses. Since LTH is abnormal in SSc patients, we aimed at testing whether LTH could be a prognostic tool for the onset of digital ulcers.We prospectively enrolled 51 patients with SSc. Nailfold capillaroscopy and LTH were recorded at baseline, and patients were followed for 3years.
No patient with a LTH peak/plateau ratio ≥1 (n=19) developed digital ulcerations during the 3year follow-up (100% negative predictive value), while 6 out of 32 patients with a LTH peak/plateau ratio <1 at enrolment presented with finger pad ulcerations within 3years (p=0.05). In contrast, when lidocaine/prilocaine was applied to the finger pad, no relationship between thermal hyperemia and digital ulcerations was observed.
A LTH peak/plateau ratio on the finger pad greater than 1, which can easily be determined in routine clinical practice, could be used to reassure patients, whatever the subtype of SSc, about the low probability of future digital ulceration. However, the prognostic value of this parameter should be confirmed in a larger cohort.