Eruptive Vellus Hair Cysts: A Systematic Review

The document summarized findings from a systematic review of 158 papers on eruptive vellus hair cysts (EVHC), which after exclusions, provided data on 220 cases. The average age at diagnosis was 23.9 years, with the condition often appearing at birth or within the first three decades of life. EVHC is more common in White individuals and slightly more frequent in women, particularly of Asian and Hispanic descent. The condition presents as skin-colored papules and is characterized histologically by mid-dermal cysts containing vellus hair shafts. Subgroups of EVHC were identified, including familial and late-onset cases, suggesting an autosomal dominant inheritance with incomplete penetrance. EVHC is primarily a cosmetic concern, persists chronically, and has few effective treatments. The review highlighted the need for further research on genetic and tissue analysis, non-invasive diagnostic procedures, and therapeutic trials, as current treatment evidence is limited to isolated case reports.