Lichen planus (LP) and lichen sclenosis (LS) are chronic, non-contagious inflammatory conditions affecting the skin and mucous membranes. Both involve an immune-mediated response, leading to changes in skin texture and appearance. Although they share the term “lichen” due to similar microscopic features, their clinical course, primary locations, and long-term impact differ substantially. This comparison provides an overview of these differences to understand the unique severity and management requirements of each condition.
Distinct Clinical Presentations
Lichen planus typically manifests as distinct lesions on the skin. These lesions are commonly purple, polygonal, and intensely itchy, appearing most frequently on the flexor surfaces of the wrists, forearms, and ankles. A hallmark sign of LP is the presence of Wickham’s striae—fine, lacy, white lines visible across the surface of the papules or, most often, on the buccal mucosa inside the mouth.
Approximately half of individuals with LP develop oral involvement, presenting as painful erosions, ulcers, or the characteristic white, net-like pattern. Genital LP can also occur, sometimes involving the vagina, and may present as painful erosions or papules on the vulva or glans penis. The widespread nature of LP, affecting various skin and mucosal surfaces simultaneously, distinguishes its presentation.
In contrast, Lichen Sclerosus (LS) predominantly affects the anogenital region, with over 85% of cases localized to the vulva and perianal skin in women, or the foreskin and glans in men. LS lesions appear as white, thin, and wrinkled patches, often likened to parchment paper, resulting from atrophic and fragile skin. Intense itching (pruritus) is the most common symptom, which, combined with skin fragility, often leads to bruising, tearing, and fissures. Unlike LP, LS rarely affects mucous membranes like the lining of the mouth or the inside of the vagina, which is a key diagnostic difference.
Understanding Underlying Causes and Risk Factors
The exact cause for both Lichen Planus and Lichen Sclerosus remains unknown, but both are classified as chronic autoimmune disorders involving an abnormal T-cell-mediated response. This means the immune system mistakenly targets and attacks specific cells in the skin and mucosa. The onset of LP has been linked to potential triggers, including certain medications, contact allergens, or viral infections such as Hepatitis C.
LP affects both sexes equally and is most common in adults between the ages of 30 and 60. A phenomenon known as the Koebner response is often observed in LP, where new lesions form in areas of skin trauma, such as a scratch or surgical site. Genetic susceptibility is also suspected for both conditions, as a family history increases the likelihood of developing either LP or LS.
Lichen Sclerosus shows a strong demographic preference, being significantly more common in women, with ratios ranging from 6:1 to 10:1 compared to men. It primarily affects postmenopausal women, though it is also diagnosed in prepubertal girls and can occur at any age. LS is often associated with other autoimmune diseases, particularly thyroid disorders, vitiligo, and autoimmune anemia, suggesting a systemic predisposition. While LS can also be triggered by local trauma, its strong hormonal and autoimmune associations distinguish its risk profile from LP.
Comparing Long-Term Consequences
The long-term consequences are where the differences in severity become most apparent. Lichen Sclerosus carries a high risk of causing permanent architectural change and functional impairment, especially in the genital region. Chronic inflammation and subsequent healing lead to significant scarring, resulting in the fusion of the labia, burying of the clitoris under scar tissue (phimosis), and narrowing of the vaginal opening (introital stenosis). These anatomical changes can cause chronic pain, severe discomfort during intercourse (dyspareunia), and difficulties with urination or defecation.
LS is strongly associated with an increased risk of developing vulvar squamous cell carcinoma (VSCC), a form of skin cancer. The risk of developing VSCC in women with LS is estimated to be between 2.2% and 5% over a lifetime, necessitating lifelong monitoring. This malignancy risk is a primary factor in designating LS as severe. Lichen Planus, conversely, is generally less associated with extensive functional impairment or scarring, unless it is a severe erosive or hypertrophic form.
However, erosive Lichen Planus of the vulva or vagina can also cause significant scarring, adhesions, and introital narrowing, leading to functional issues similar to LS. For LP, the main cancer risk is linked to the oral form (OLP), which is considered a precancerous condition. Studies suggest that approximately 1% to 3% of OLP cases may progress to oral squamous cell carcinoma, making careful surveillance of persistent erosive lesions necessary. While both conditions carry a malignancy risk, the overall risk of functional impairment and significant anatomical distortion is generally higher in anogenital LS.
Current Treatment Goals and Management
The primary treatment goal for both Lichen Planus and Lichen Sclerosus is to suppress the inflammatory response, alleviate symptoms, and prevent disease progression. Neither condition is typically curable, requiring long-term management to control flare-ups. High-potency topical corticosteroids, such as clobetasol propionate, serve as the first-line therapy for both LP and LS, applied directly to the affected skin or mucosa.
For Lichen Sclerosus, consistent and lifelong use of potent topical steroids is necessary, as it manages symptoms and significantly reduces the risk of malignant transformation. Due to the high potential for permanent scarring, LS management often requires surgical intervention for functional restoration, such as releasing labial fusions or widening a narrowed vaginal opening. Regular follow-up examinations are required to monitor for early signs of cancer development.
Lichen Planus management also relies on topical steroids, but extensive or refractory cases frequently employ systemic therapies. These include oral corticosteroids, immunosuppressive agents, or phototherapy, particularly for widespread cutaneous or severe erosive oral involvement. Vulvovaginal LP often requires topical medications along with recommendations for vaginal dilation to prevent scarring that can lead to complete obliteration of the vaginal canal.