Lichen planus (LP) is a chronic, but benign and self-limited disease of the skin and/or oral mucosa with an unknown etiology. It is not life-threatening in most cases. However, it can cause some complications, such as:

Hyperpigmentation

Lichen planus is a self-limited skin condition and remission usually occurs within 18 months. However, even after the lesions clear, the skin may remain discolored as a result of post-inflammatory hyperpigmentation. This tends to be more noticeable in people with darker skin.

Scarring alopecia

In lichen planopilaris, the lichen planus lesions affect the scalp, presenting as reddish plaques surrounding hair follicles, with itching and scaling. These may cause scarring, with resultant plugging of the hair follicle and hair loss.

Erosive LP

Cutaneous LP lesions can occur on the genital skin, such as the vulva or inside the vagina, or over the penile or scrotal skin. When ulcers develop at these sites, they lead to severe pain and burning. The vaginal or vulval skin may become red and raw.

Oral lichen planus is sometimes associated with the formation of mouth ulcers. This may cause severe soreness, a burning sensation on the ingestion of hot foods and fluids, and pain sufficient to interfere with the quality of life.
Secondary fungal or bacterial infections of the erosions or ulcers may also occur, such as candidiasis.

Dyspareunia

As a result of these changes, dyspareunia is inevitable and very distressing. Persistent symptomatic labial adhesions can also develop and aggravate the problem, necessitating operative approaches (in cases when the inflammatory process is suppressed).

Scarring of the female genital region

Vulval or vaginal erosions may become widespread. Their outcome is often scarring of the vulva or the vagina, which may lead to:

• urethral narrowing
• fusion of the labia
• stenosis of the vagina or of the vulval orifice
• obstruction and pain during the flow of urine
• dyspareunia

Esophageal stenosis

Esophageal lichen planus may cause significant dysphagia, and later esophageal strictures. This may lead to malnutrition, weight loss and aspiration pneumonia. Due to its rare occurrence, this condition is sometimes misdiagnosed as reflux esophagitis, further complicating the situation.

Psychological sequelae

Severe and resistant forms of erosive lichen planus may cause a major reduction in the quality of life, with difficulties in eating, drinking, urination, defecation and sexual functions. There is a higher incidence of consequent depression, stress and anxiety due to vulvar, vaginal, oral or esophageal pain and stenosis in these patients.

Malignant transformation

Oral or cutaneous lichen planus may sometimes be of the erosive or ulcerative type. This is seen in only about 2% of cases. Here, the plaques or papules that develop over the penis, the vulva, or the mucous surfaces of the gums, the cheeks, or the sides of the tongue, may become ulcerated.

When these ulcers persist for a long time (such as years), they may undergo cancerous change to become oral, penile or vulvar cancer, usually squamous cell carcinomas. This complicates the atrophic and erosive types of lichen planus.
Medical advice is to be sought if:

• There is any persistent change in the appearance of the lesions inside the mouth or on the skin.
• Lichen planus continues unchanged, or worsens, despite appropriate treatment.
• Oral LP is thought to be triggered by some medications, which need to be stopped, or by some medical conditions, which require proper treatment.