Peripheral blood eosinophilia is associated with the presence of skin ulcers in patients with systemic sclerosis.

The role of eosinophil in systemic sclerosis (SSc) is still controversial. In the present study, the relationship between skin ulcers and peripheral blood eosinophilia were analyzed in patients with SSc. We retrospectively investigated the clinical records of all patients who were diagnosed with SSc on the basis of American College of Rheumatology/European League Against Rheumatism 2013 criteria, and were followed up for more than 2 years at Wakayama Medical University. As a result, maximum eosinophil counts during the 2-year follow-up period were 20-983/mm3 (median, 270), whereas maximum eosinophil percentages were 0.5-14.1% (median, 5.3%) in peripheral blood of 47 SSc patients. On the other hand, patients with skin ulcers during the 2-year follow up showed significantly increased maximum eosinophil counts compared with those without (median, 520 vs 228/mm3 ; P = 0.0001). Maximum eosinophil percentage was also significantly higher in patients with skin ulcers (median, 9.7% vs 4.6%; P = 0.00001). To note, in four of the nine patients with skin ulcers, the timing of emerging of the maximum eosinophil counts was associated with the ulcer development during the 2-year follow up. These results suggest that eosinophils are involved in the pathogenesis of vascular dysfunction of SSc. Larger studies should be performed to clarify the exact mechanism of ulcer formation caused by eosinophilia in SSc patients in the future.