Association of skin hyperpigmentation disorders with digital ulcers in systemic sclerosis: Analysis of a cohort of 239 patients

Background: Skin pigmentation disorders in systemic sclerosis (SSc) have been sparsely described in the literature. Nevertheless, they could be a diagnostic and/or severity marker. Objectives: To assess the association between pigmentation disorders and systemic involvement in patients with SSc. Methods: A total of 5 patterns of skin pigmentation disorders were defined: diffuse hyperpigmentation; hyperpigmentation of sun-exposed areas; hypopigmentation of the head, neck, and/or upper part of the chest; acral hypopigmentation; and diffuse hypopigmentation. Results: A total of 239 patients were included; 88 patients (36.8%) had skin pigmentation disorders as follows: diffuse hyperpigmentation and hyperpigmentation of sun-exposed areas in 38.6% (n = 34) and 27.3% (n = 24) of patients, respectively; hypopigmentation of the face, neck, and/or chest in 10.2% of patients (n = 9); diffuse hypopigmentation in 12.5% (n = 11); and acral hypopigmentation in 17% (n = 15). Diffuse hyperpigmentation was associated with diffuse SSc (P = .001), increased modified Rodnan skin score (P = .001), and shorter duration of Raynaud phenomenon (P = .002) in univariate analysis but not in multivariate analysis. Moreover, diffuse hyperpigmentation was associated with digital ulcers (P = .005), as confirmed by multivariate analysis (odds ratio, 2.96; 95% confidence interval, 1.28-6.89). Limitations: This was a single-center retrospective study of a cohort of patients with SSc. Conclusion: Screening for skin pigmentation disorders could be useful in the management of patients with SSc to identify those with a high risk of development of digital ulcers, which is a symptom of vascular involvement in SSc.