BACKGROUND: Lichen sclerosus (LS) is a chronic inflammatory condition that mainly affects genital skin. It causes distressing symptoms that impact daily quality of life, as well as progressive anatomical changes and a potential risk of cancer. Vulval LS is often misdiagnosed and treatment delayed. If nonexperts can be supported to identify clinical features of LS, they may diagnose the condition sooner and commence timely treatment or refer a patient for assessment and confirmatory biopsy. OBJECTIVES: To reach international expert consensus on clinical diagnostic features for vulval LS. METHODS: 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 features. Responses from round 1 were summarized and presented in rounds 2 and 3, along with additional features suggested by participants. Any items rated as 'very important/critical' or 'not important' that met the definition of consensus were removed from subsequent rounds. In round 4, items that were rated 'important but not critical' were ranked in order of their importance. Consensus was defined a priori, and all rounds were conducted anonymously. RESULTS: In total, 47 participants from 14 countries completed round 1, with 42 (89%) retained by round 3 when consensus was determined. Round 4 was completed by 36 (77%) participants. Participants completing all four rounds predominantly included healthcare professionals (n = 28/36
78%) and patient support group representatives (n = 7/36
19%). In round 1, 21 diagnostic features were rated. Participants suggested an additional 10 features, which were subsequently added to the round 2 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 rated as 'important but not critical' and participants subsequently ranked them in the fourth round. CONCLUSIONS: Experts agreed on 5 critical diagnostic features for vulval LS in adults and an additional 12 features that may also be important. Future research should assess these clinical features for diagnostic validity through a multicentre diagnostic test accuracy study.