Lichen sclerosus (LS) is a chronic dermatosis characterized by an initial short inflammatory phase followed by chronic scarring and skin atrophy. It is a disease primarily of anogenital skin in both males and females. It is more common in females, with 2 peaks in age distribution: 1) prepubertal children, and 2) postmenopausal women. Childhood and adolescent cases in boys have increasingly been recognized.

The pathogenesis of LS is unknown, but an autoimmune mechanism with genetic predisposition is hypothesized. Some studies implicate Borrelia spp and Epstein-Barr virus (EBV) infection, and trauma and hormonal influences have also been investigated.

Anogenital LS may be a chronic relapsing disease that may cause atrophy and scarring, functional impairment, and malignancy. Additionally, LS is one of the most common causes of chronic vulvar symptoms in adult females.

Clinically, over 85% of lesions are found on anogenital skin. In this location, LS usually presents as dry, tender, and severely pruritic atrophic white plaques. In females, characteristic sites include the clitoris and clitoral hood, interlabial sulci, labia minora, and perineum. Plaques can progress to cause fusion of labia minora to adjacent mucosa, and ultimately, fusion can involve clitoral hood and clitoris. Sclerosis of the vaginal introitus, with resultant dyspareunia, can also occur. Secondary erosion or ulceration may lead to burning and pain, especially after micturition. Difficulty in voiding may be seen in the later stages.

The majority of cases of male genital LS occur in uncircumcised men. The glans and prepuce are most frequently affected. Meatal involvement may occur. Scarring complications include urinary obstruction, ulceration, painful erection, and phimosis. There may also be diminished sensation of the glans and sexual dysfunction.

Squamous cell carcinoma can arise in untreated genital lesions.

LS may also occur on extragenital skin and rarely on the oral mucosa. The Koebner phenomenon, with development of LS at sites of trauma, has been reported. Extragenital LS is frequently asymptomatic; however, it can also be xerotic and pruritic. It most commonly presents as ivory-colored, atrophic papules and/or plaques with follicular accentuation.