Lichen sclerosus (LS) is a common autoimmune disorder of the genital skin. It affects 1/900 women with an age peak in the sixth decade of life. LS is a chronic inflammatory condition affecting the genital, perineal, and perianal areas and causes itching, burning, pain, and soreness. Histologically, LS is characterized by epidermal atrophy, hyperkeratosis, follicular plugging, degeneration of the basal layer, and subepidermal hyalinization of collagen in the papillary dermis with a lymphocytic infiltrate. Affected women typically suffer significant long-term genital damage including scarring, fusion of the vulval labia, narrowing of the vaginal opening, dyspareunia, and burying of the clitoris. In addition, LS is associated with an increased risk of vulvar cancer.

Treatment options of LS include topical steroids such as clobetasol, topical immunomodulators such as tacrolimus, and non-ablative laser treatment. In a systematic review of the literature with 7 studies and 249 participants, clobetasol achieved improvement rates and remission rates of 70% to 89% and 20% to 35%, respectively. In comparison, non-ablative laser treatment leads to significant improvements in vulvar itching, dryness, pain, and dyspareunia in 50% to 85% of women with remission rates of up to 80% after 14 years of follow-up. Although both treatments are well documented and used in clinical practice, direct comparative studies assessing the efficacy of topical corticosteroids versus laser treatment in women with LS are rare. For example, in a PubMed literature search (search date 2021-03-14; search terms: lichen sclerosus, laser, corticosteroids, steroids, clobetasol, randomized) only one randomized trial was identified. In this study, the authors included 40 women with LS and compared 3 applications of non-ablative laser 2 weeks apart with 4 weeks of twice daily (2 weeks), once daily (1 week), and every other day (1 week) of topical clobetasol 0.05% cream. After 3 months of treatment laser-treated women had a significantly higher sum score (including burning, itching, and pain) measured on an 11-step visual analogue scale (VAS). Both treatments demonstrated histological improvement with reductions of inflammatory hallmarks in skin biopsies.

Given this body of evidence, more high-quality studies are needed to define the superiority/inferiority of the different available treatment options such as non-ablative laser and topical corticosteroids. Therefore, a prospective, randomized trial comparing non-ablative CO2 laser treatment and topical clobetasol 0.05% will be conducted. The aim of this prospective, randomized, open-label, comparative trial is to establish or refute the superiority of 3 courses of non-ablative treatment by CO2 laser every 14 days compared to topical clobetasol 0.05% (daily in month 1, every other day in month 2, and 3 times/week in month 3) for 3 months. The primary endpoint of this study is a sum score including the pathognomonic symptoms of LS, namely vulvar burning, itching, and pain, each measured on an 11-step VAS. Secondary endpoints will include the physician-scored rate of visual improvement (measured on an 11-item VAS), side effects, and patient-reported outcomes such as subjective overall improvement, general satisfaction, and quality of life (measured by a validated questionnaire for vulval disorders; i.e. the VDQI (Vulval Disease Quality of Life Index).