Causes of Vulvar Lichen Sclerosus
VLS does not have a single identified cause. What we do know is that it is an autoimmune disease with a clear genetic component—and that this has specific implications for treatment and follow-up.
The Autoimmune Origin of Vulvar Lichen Sclerosus
Vulvar lichen sclerosus is an autoimmune disease. This means that the patient’s immune system generates an inflammatory response against the vulvar tissue itself—as if it identified it as an external threat. This chronic inflammatory response is what produces the characteristic changes in the skin and mucous membranes of the disease.
Several facts support this autoimmune origin:
Association with Other Autoimmune Diseases
Patients with VLS have a higher prevalence of autoimmune diseases such as Hashimoto's thyroiditis, vitiligo, rheumatoid arthritis, lupus, and pernicious anemia. This association is statistically significant and is one of the strongest arguments in favor of the autoimmune origin.
Presence of Autoantibodies
In some patients with VLS, antibodies against extracellular matrix proteins of the vulvar tissue are detected. Their presence is not universal, but it reinforces the autoimmune hypothesis.
Response to Immunomodulatory Treatment
The fact that topical corticosteroids—which act by reducing the local inflammatory response—are the most effective treatment for VLS is consistent with its autoimmune nature.
Genetic Predisposition and Hormonal Factors
Hereditary Component
VLS has a documented genetic component. Women with a family history of VLS or other autoimmune diseases have a higher risk of developing the disease. Genetic association studies have identified variants in genes related to the immune system that are more frequent in patients with VLS. This does not mean that VLS is hereditary in the classic sense—it is not transmitted directly from mother to daughter—but rather that there is a genetic predisposition that, combined with other factors, can lead to the development of the disease.
Hormonal Factors
The higher prevalence of VLS in perimenopause and postmenopause suggests a modulating role of estrogens in the disease. The drop in estrogens during menopause could reduce the protection that these hormones offer to vulvar tissue against the autoimmune inflammatory response. However, the direct causal relationship between hypoestrogenism and VLS is not completely established. VLS also appears in premenopausal women and prepubertal girls—when estrogen levels are low for other reasons—which suggests that the hormonal factor is modulating, not the sole cause.
Local Factors That May Influence
In women with genetic and autoimmune predisposition, certain local factors can act as triggers or aggravating factors:
Local Trauma
The Koebner hypothesis—whereby lesions of some inflammatory diseases appear in areas of previous trauma—has support in VLS. Repeated trauma to the vulvar area could trigger or aggravate the disease in predisposed women.
Chronic Irritation
Prolonged exposure to local irritants—harsh soaps, scented pads, tight synthetic clothing—can maintain a state of local inflammation that favors disease activity.
Infections
Some studies have investigated the relationship between Borrelia burgdorferi and VLS, although the data are inconsistent and this hypothesis does not have sufficient support in current clinical guidelines.
What Does Not Cause Vulvar Lichen Sclerosus
There are several myths about the causes of VLS that should be clarified:
> VLS is not contagious. It is not transmitted through sexual contact, clothing, or any other route. It is not a sexually transmitted infection.
> VLS is not caused by soaps or hygiene products. Local irritants can aggravate symptoms in patients who already have VLS, but they do not cause the disease.
> Stress does not cause VLS. Stress can modulate the immune response and aggravate symptoms of many autoimmune diseases, but it is not a cause of VLS.