Co-occurring erosive vulvovaginal lichen planus (LP) with vulvar lichen sclerosus (LS) may be an underrecognized condition, carrying a higher risk for differentiated vulvar intraepithelial neoplasia than either condition alone, according to researchers at the University of California, Irvine School of Medicine.

Their findings, presented as a poster at the American Academy of Dermatology (AAD) 2026 Annual Meeting and also published in JAAD Case Reports, may warrant earlier consideration of systemic immunomodulators, they said.

LS/LP overlap syndrome “is not new but remains underappreciated, and recognizing it — particularly in patients with known LS — is critical given the potential for more severe disease and consideration of systemic therapy,” reported Christina N. Kraus, MD, and coauthors.

Overlap syndrome is supported by a pattern of anatomic involvement, they explained.

Isolated LS is rarely oral and usually spares the vagina, with vulvar involvement typically presenting as pruritus, atrophic white plaques, and progressive scarring.

In contrast, vaginal involvement occurs in 70% of LP cases and involves painful mucosal erosions of both the vulva and vagina, sometimes resulting in vaginal stenosis, with oral LP co-occurring in 25% of cases.

The study was based on a retrospective chart review from a tertiary vulvar dermatology clinic and included 13 patients with confirmed vulvar involvement in both conditions.

The rate of vulvar intraepithelial neoplasia in the cohort was 15%, exceeding expected rates for either LS or LP alone (7% and 3%, respectively), they reported. “This may reflect referral bias at a tertiary center but also suggests a more severe disease phenotype, warranting further study,” they added. 

The mean age at diagnosis of the overlap syndrome was 69.2 years, which is later than the typical onset for isolated vulvar LS or erosive vulvovaginal LP, they reported.

Four patients (30.7%) had autoimmune comorbidities, including Hashimoto thyroiditis, Sjögren syndrome, psoriasis, and celiac disease.

Oral LP was found in six patients (46.2%) and lichen planopilaris in four patients (31%).

“The frequent association with lichen planopilaris underscores the importance of full-body skin, scalp, and oral examination and reciprocal vulvar evaluation in patients with oral and cutaneous LP,” noted the researchers.

All patients were treated with a high-potency topical corticosteroid, such as clobetasol or fluocinonide, but 46% also used systemic therapy because topicals alone did not adequately control the condition.

Additionally, 69% also used topical estrogen, and 15% used vaginal dilators.

The findings underscore the need for a comprehensive mucocutaneous examination (vulva, vagina, oral cavity, and scalp) and earlier consideration of systemic immunomodulatory therapy, given the potentially severe and refractory clinical presentation of LS/LP overlap syndrome, they concluded.

“This study highlights a clinically important overlap phenotype as a distinct entity, rather than a simple coincidence,” Amaris Geisler, MD, dermatologist with a special interest in vulvar dermatitis at Olansky Dermatology & Aesthetics, and adjunct assistant professor of dermatology at Emory University in Atlanta, told Medscape Medical News. Geisler was not involved in the study.

“Vulvar LS and vulvar LP are already two individually underrecognized entities,” she added. “Overlap disease may be more severe and refractory than either entity alone, which — aside from the significant implications for quality of life, sexual function, and pain — should prompt providers to consider an earlier and more aggressive treatment approach addressing inflammatory, anatomic, and malignant sequelae.”

The study’s findings of an elevated rate of differentiated vulvar intraepithelial neoplasia and later age at diagnosis for the combined phenotype also “present a challenge,” Geisler noted. Older patients are often past the screening cutoff for routine pap smears and undergo fewer gynecologic exams, “so it becomes our responsibility to correctly identify these high-risk patients and closely surveil them,” she said.

“I urge readers to refer to the table in their case report publication for a list of the biologics and small-molecule inhibitors that were used off-label for systemic treatment,” she added, noting that “while estrogen was recorded as part of the treatment plan, estrogen is used to treat concomitant genitourinary syndrome of menopause rather than the inflammatory condition itself.”

The study authors pointed out that despite their clinic’s diverse population, all patients in the cohort were White, so there were potential diagnostic or access-related disparities. “Further studies should aim to incorporate skin of color patients, as these diseases do affect this population,” Geisler noted. 

The researchers reported receiving no funding for the study. Kraus, the recipient of a Dermatology Foundation Career Development Award, reported being a consultant for Nuvig Therapeutics and LEO Pharma and an investigator for Incyte Corporation. Geisler reported having no relevant conflicts of interest.

Kate Johnson is a Montreal-based freelance medical journalist who has been writing for more than 30 years about all areas of medicine.