Lichen Sclerosus

Chronic inflammatory disease which mainly affects the anogenital region. It is predominantly prevalent in females (F:M ratio = 8:1) and in 70% of cases arises befoe the age of 7.

Signs and symptoms

Lichen sclerosus (LS) affects the anogenital region and presents with whitish, atrophic plaques with clearly-defined edges, which may be in the typical figure-of-8 or hour-glass distribution. There may also be haemorrhagic lesions, purpura, erosions and cracks caused by scratching. The degree of severity is variable. Sometimes recurrent inflammatory forms of erythematous vulvitis may precede the onset of LS by months or years. Subjectively pruritus is the main symptom; sometimes there is also pain on defecation with constipation or dysuria. LS may also present in an extragenital location, isolated or together with genital lesions. In the initial stages of extragenital lesions, typical blackish follicle root sheaths are observed on the surface of the plaques. Dermoscopy is a useful diagnostic tool, quick and non-invasive.

Course

LS heals spontaneously before puberty. In the prolonged forms, there may be permanent scarring such as burial of the clitoris in its hood, reabsorption of the labia minora or stenosis of the orifice. Sometimes there may be residual achromic sequelae which may last a long time.

Differential diagnosis

Irritative dermatitis should be considered for the initial erythematous forms of LS, cicatricial pemphygoid for the rare bullous forms, and vitiligo for achromic sequelae. The main differential diagnosis for the forms with haemorrhagic lesions should consider sexual abuse.

Balanite xerotica obliterans or lichen sclerosus and atrophicus of the glans and prepuce.

It presents on the prepuce with phimosis which in 80-90% of cases is due to LS. The glans may also be affected and the lesions initially tend to be located on the frenulum. Unlike females, LS in males does not affect the perianal area.
The therapy of first choice is surgical and consists of circumcision. Medical therapy should be considered when the glans is affected. Due to the risk of recurrence, higher in obese subjects, post-surgical follow-up is required. In the case of stenosis of the external meatus which may develop even after months or years, a urine flow test should be conducted, and if the flow is under 10 ml/s, meatotomy. To reduce the risk of recurrence, the operation should come after the treatment of LS with medical therapy (topical steroids or topical calcineurin inhibitors, pimecrolimus or tacrolimus).

Treatment

Medium- or high-potency topical steroids are used, generally a single agent, for a period varying between one or two months or at least until complete clinical recovery. In the case of relapse, the treatment should be repeated. As second choice topical calcineurin inhibitors, pimecrolimus or tacrolimus, are used.

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