Researchers who tallied symptoms and physical exam findings observed fewer statistically significant differences between LS and vitiligo patients than expected, and LS and vitiligo were sometimes misdiagnosed as each other.
“LS must be treated aggressively to prevent long-term sequelae such as permanent scarring and vulvar squamous cell carcinoma, making an accurate diagnosis crucial,” the authors write in a poster they presented at the annual meeting of the Society for Pediatric Dermatology.
LS is symptomatic and has multiple exam findings, but once treated or quiescent, the discoloration can persist and create diagnostic uncertainty, lead study author, a pediatric dermatologist at Children’s National Hospital, Washington, told this news organization following the SPD meeting.
The diagnostic uncertainty is especially true in patients with darker skin tones, who may have vitiligoid LS, an LS variant that has overlapping features of both LS and vitiligo.
Vitiligoid LS “presents clinically as a depigmented symmetric white vulvar and perianal white patch, often with minimal signs of inflammation, but is symptomatic and appears consistent with LS on histopathology,” Dr. Habeshian said.
“In our experience, in patients with medium to dark skin tones, there is a variable amount of repigmentation after treating LS,” she added. “After use of high potency topical corticosteroids, some patients almost completely repigment, while others have minimal repigmentation, and this can fluctuate over time, sometimes independent of other signs or symptoms of a flare up. This can lead to diagnostic confusion. For example, if an LS patient is examined after treatment, and their symptoms have resolved, they may subsequently be given a diagnosis of vitiligo.”
In the study, Dr. Habeshian and her coauthors aimed to characterize differences in LS and vitiligo based on history, physical exam, and demographic findings at the time of the initial clinic visit. She and her colleagues extracted and reviewed the medical records of 98 patients with a diagnosis of LS or vitiligo who were seen at a joint pediatric dermatology-gynecology vulvar clinic over 6.8 years. The median and mean age of the study population at diagnosis was about 6 years, with ages ranging from 2 to 20. The team used descriptive statistics and Z tests for data analysis.
The researchers found that pruritus, constipation, and dysuria were the most common symptoms experienced by both LS and vitiligo patients. All were experienced more frequently by LS patients, but only pruritus reached statistical significance (P = .040). Other symptoms experienced only by LS patients included vulvar pain, bleeding, and pain with defecation.
Meanwhile, apart from hypopigmentation and erythema, all physical exam findings were more frequent in LS patients, compared with vitiligo patients, including fissures and purpura/petechiae, but only epidermal atrophy and figure-of-8 distribution of hypopigmentation reached statistical significance (P values of .047 and .036, respectively).
In other findings, LS and vitiligo were misdiagnosed as each other 15 times. Nearly half of the misdiagnoses (46.7%) were made in Black patients, who composed 38.8% of all patients in the study.
“I suspect that some vitiligo cases that were previously ‘misdiagnosed’ as LS were actually LS that just didn’t repigment and then were labeled as vitiligo in the chart,” Dr. Habeshian said.
“And some of those LS cases that previously were misdiagnosed as vitiligo likely had other more subtle LS findings that were missed (shininess and wrinkling of the skin, small fissures, constipation) or that were attributed to comorbid irritant contact dermatitis or another condition,” she said. “It was interesting to see that even in a vulvar dermatology clinic there can be confusion between these diagnoses because the literature on pediatric LS in darker skin tones is so sparse.”
She emphasized that a close exam and detailed history are needed to properly diagnose patients with anogenital skin conditions.
“Don’t forget to ask about constipation and urinary symptoms as well as psychosocial and, in the appropriate patient, sexual and reproductive function,” Dr. Habeshian said. “Based on my experience, pediatric LS is much more common in our community than the literature would suggest. Its psychosocial impact is tremendous but not well documented, particularly in pediatric patients. In my experience, the longer LS is misdiagnosed or mistreated, the more challenging it becomes to manage. You don’t want to miss LS.”
She acknowledged certain limitations of the study, including the fact that photographs were not available for review for many of the earlier years of the clinic. “Therefore, we had to depend on the diagnosis given at the time of the visit,” she said. “This likely accounts in part for the smaller number than expected of significant exam and history findings between LS and vitiligo. We need further studies utilizing a standardized approach to accurate diagnosis.”
Her coauthors were Nikita Menta, Aneka Khilnani, MS, and Tazim Dowlut-McElroy, MD. The researchers reported having no financial disclosures.