P078 Establishing diagnostic criteria for vulval lichen sclerosus (SHELLS): an international electronic-Delphi consensus study

Lichen sclerosus (LS) is a chronic inflammatory condition mainly affecting genital skin. It causes distressing symptoms that impact daily quality of life, results in progressive anatomical changes and has a potential risk of cancer. There is no defined set of diagnostic criteria for vulval LS. As a result, vulval LS is often misdiagnosed and improperly treated. The objectives of this study were to reach international expert consensus on clinical diagnostic criteria for vulval LS. Between March and May 2023, a four-stage electronic-Delphi consensus exercise was conducted. In the first three rounds, participants were asked to rate the importance of a list of clinical criteria. Responses from round one were summarized and presented in rounds two and three, along with additional criteria suggested by participants. Any items that met the definition of consensus as ‘very important/critical’ or ‘not important’ were not voted on again in subsequent rounds. In round four, items that met agreement for ‘important but not critical’ were ranked in order of their importance. Consensus was defined a priori, and all rounds were conducted anonymously. In total 47 participants from 14 countries completed round one, with 42 (89%) retained by round three when consensus was determined. Round four was completed by 36 (77%) participants. Participants completing all four rounds predominantly included healthcare professionals (78%, n = 28) and patient support group representatives (19%, n = 7). In round one, 21 diagnostic features were voted on. Participants suggested an additional 10 features that were subsequently added to the round two survey. After three rounds, consensus was achieved for five diagnostic features: whiteness, itch, changes in anatomy, burying of the clitoral area, and improvement in response to topical steroids. There were also 12 features voted as ‘important but not critical’, and participants subsequently ranked them in the fourth round. Experts have agreed on five critical diagnostic features for vulval LS in adults, and an additional 12 features that may also be important. Future research should assess these features for diagnostic validity through a multicentre diagnostic test accuracy study.