Quantitative nailfold capillary microscopy findings in patients with acrocyanosis compared with patients having systemic sclerosis and control subjects

Background: The morphologic capillary microscopy (capillaroscopy) pattern o f acrocyanosis is characterized by hemorrhages, pericapillary edema, and wi dened capillaries. These findings can result in a difficult differential di agnosis with systemic sclerosis (SSc). Objective: Me sought to quantify the characteristics of the capillaroscopy pattern that distinguishes patients with acrocyanosis from patients with SS c and control subjects. Methods: A videomicroscope with fiberoptic illumination and personal comput er-based image processing was used to measure capillary density, giant capi llaries, loop width, and arterial and venous limbs in 10 patients with acro cyanosis, 10 patients with SSc, and 10 healthy control subjects. Results: Acrocyanotic patients differed in every quantitative parameter bot h from control subjects and patients with SSc. In particular, capillary den sity, which was reduced compared with that of control subjects, was much hi gher than that of patients with SSc: one giant capillary per finger was obs erved in 2 patients with acrocyanosis, whereas more than 2 giant capillarie s per finger were observed in each patient with SSc. Conclusion: These differences may aid in making the distinction between the capillaroscopy patterns in acrocyanosis and SSc.