Lichen sclerosus is a chronic inflammatory skin condition that most commonly affects the vulva and perianal skin. It is thought to be autoimmune in origin and is unrelated to hygiene, sexually transmitted infections, or anything the patient has done wrong.
It can occur at any age, but is most common in postmenopausal women and in young girls. It also affects men (on the penis) as balanitis xerotica obliterans. Lichen sclerosus is not contagious.
Without treatment, lichen sclerosus tends to cause progressive thinning, whitening, fissuring, and scarring of the vulvar skin. Over many years, untreated disease carries a small but real risk of vulvar squamous cell carcinoma (~2–5%). Appropriate, ongoing treatment largely prevents these complications.