The digital thermal hyperemia pattern is associated with the onset of digital ulcerations in systemic sclerosis during 3 years of follow-up

• One of the more important complications in systemic sclerosis is the digital ulcer.
• The initial peak of skin local thermal hyperemia (LTH) explores neurovascular response.
• The delayed plateau of skin local thermal hyperemia reflects endothelial function.
• Both phases of LTH are abnormal in the finger pad of systemic sclerosis patients.
• LTH peak/plateau ratio ≥ 1 is associated with a low probability of future digital ulcer.

ObjectivesOne of the most important skin complications in systemic sclerosis (SSc) is digital ulceration. 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.MethodsWe prospectively enrolled 51 patients with SSc. Nailfold capillaroscopy and LTH were recorded at baseline, and patients were followed for 3 years.ResultsNo patient with a LTH peak/plateau ratio ≥ 1 (n = 19) developed digital ulcerations during the 3 year 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 3 years (p = 0.05). In contrast, when lidocaine/prilocaine was applied to the finger pad, no relationship between thermal hyperemia and digital ulcerations was observed.ConclusionsA 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.