Effect of Epidermoid Cysts on the Efficacy of Intralesional Corticosteroid Therapy for Hypertrophic Scars and Keloids: A Prospective Pilot Study

BACKGROUND Patients with hypertrophic scars (HSs) or keloids occasionally have epidermoid cysts (ECs), and the effect of ECs on the effectiveness of intralesional corticosteroids (ILCs) treatment in these patients has not been reported. OBJECTIVE This study aims to evaluate the influence of ECs on the outcomes of ILCs treatment in patients with HSs or keloids. MATERIALS AND METHODS This prospective study included 572 patients with keloids (n = 461) or HSs (n = 111). Patients received intralesional triamcinolone acetonide injection (0.05 mL/injection) at a concentration of 40 mg/mL and every 28 days for 4 sessions, with a 1-year follow-up. RESULTS A higher incidence of ECs was observed in keloid patients (16.92%) compared with HSs patients (7.21%). Keloid patients with ECs were older (p = .008) and had a longer disease duration (p = .0148), higher Vancouver scar scale (VSS) scores (p = .04), and greater thickness (p = .006). Keloid patients with ECs showed less improvement in VSS scores (p < .0001) and thickness (p < .0001) after ILCs treatment, with a higher recurrence rate (p < .0001). The overall complication rate in keloid patients with ECs after ILCs treatment was 49.51%. CONCLUSION Epidermoid cysts under keloids were associated with a poor response to ILCs therapy. Therefore, it is recommended to incorporate ultrasonography as a routine examination for keloid patients to aid in better decision making in clinical practice.