Background Telangiectasia macularis eruptiva perstans (TMEP) has not been fully characterized. Objective We sought to estimate the frequency and clinical characteristics of TMEP in a cohort of adult patients with cutaneous mastocytosis, and to assess the presence of systemic involvement. Methods We included all consecutive patients evaluated for cutaneous mastocytosis in 2 centers: the Mastocytosis Competence Center of the Midi-Pyrénées from May 2006 to December 2013, and the French Reference Center for Mastocytosis from January 2008 to September 2013. Skin phenotype, histopathology, presence of KIT mutation in the skin, and assessment of systemic involvement according to World Health Organization (WHO) criteria were prospectively investigated. Results Of 243 patients with cutaneous mastocytosis, 34 (14%) were given a diagnosis of TMEP. The diagnosis of systemic mastocytosis was established in 16 patients (47%) with TMEP. Three patients (9%) had aggressive systemic mastocytosis (C-findings according to WHO). In all, 32 patients (94%) exhibited at least 1 mast cell activation–related symptom. Limitations Patient recruitment was undertaken at 2 referral centers with expertise in the diagnosis and treatment of mastocytosis so that the clinical findings and incidence of systemic involvement may be overestimated in comparison with the overall population of patients with TMEP. Conclusion TMEP accounts for about 14% of patients with cutaneous mastocytosis. The disease manifests as mast cell activation symptoms in almost all patients and can be associated with systemic involvement in about 50% of cases.