Summarization and comparison of dermoscopic features on different subtypes of rosacea

The dermoscopic features of rosacea have already been reported. However, the current findings are incomplete, and little is known about phymatous rosacea. Hence, this study aimed to summarize and compare the dermoscopic features and patterns of three rosacea subtypes (erythematotelangiectatic [ETR], papulopustular [PPR], and phymatous [PHR]) in the Chinese Han population and to evaluate whether these features differ with patients' genders, ages, and durations.Dermoscopic images of 87 rosacea patients were collected in non-polarized and polarized dermoscopy contact modes at 20-fold magnification. Dermoscopic features, including vessels, scales, follicular findings, and other structures, were summarized and evaluated.The reticular linear vessels and red diffuse structureless areas of ETR were distinctive. For PPR, red diffuse structureless areas, reticular linear vessels, yellow scales, follicular plugs, and follicular pustules were typical dermoscopic criteria. The common dermoscopic features of PHR were: orange diffuse structureless areas, linear vessels with branches, perifollicular white color, orange focal structureless areas, and white lines. The following features statistically differed among the three rosacea subtypes: reticular linear vessels (P < 0.001), unspecific linear vessels (P = 0.005), linear vessels with branches (P < 0.001), yellow scales (P = 0.001), follicular plugs (P < 0.001), perifollicular white color (P < 0.001), red diffuse structureless areas (P = 0.022), orange diffuse structureless areas (P < 0.001), red focal structureless areas (P = 0.002), orange focal structureless areas (P = 0.003), white lines (P < 0.001), follicular pustules (P < 0.001), and black vellus hairs (P < 0.001).The dermoscopic patterns of ETR are red diffuse structureless areas and reticular linear vessels. For PPR, the pattern comprehends combinations of red diffuse structureless areas, reticular linear vessels, yellow scales, follicular plugs, and follicular pustules. Meanwhile, PHR is characterized by remarkable orange diffuse structureless areas, linear vessels with branches, perifollicular white color, orange focal structureless areas, and white lines.