Telangiectatic matting are vessels less than 0.2 mm in diameter that may appear after sclerotherapy treatment of varicose or telangiectatic leg veins. It is a complication about which very little epidemiologic data have been formally accrued. Therefore, a retrospective analysis was conducted by reviewing the records of 2120 patients in a private practice setting. The overall incidence of telangiectatic matting in our patient population was 16%. To identify risk factors, in-depth comparative analysis of the databases of 160 of the patients who developed telangiectatic matting and a control group of 160 nonmatting patients was performed. Significantly more patients in the matting group were overweight, on hormones during treatment, and had both a family history and a longer duration of spider veins (p less than 0.05). Additionally, the matting group had a significantly higher proportion of people noting onset of their veins after excess hormonal states, relative to before excess hormonal states, than the nonmatting group. Age and excessive standing did not differ significantly between the two groups. The results of this study provide objective, predictive risk factors for the development of telangiectatic matting.