Lichen Planus: What It Is, How It Looks, and Causes

Lichen planus is an inflammatory dermatosis that can affect the skin, hair, nails, and mucous membranes. The diagnosis sounds alarming, but in most cases the disease is not dangerous and resolves on its own. Below is what is known about the causes, manifestations, and diagnosis of this disease.

Lichen planus — what kind of disease it is

Lichen planus is an inflammatory dermatosis with diverse manifestations: the skin, its appendages (hair and nails), and mucous membranes are involved in the process. The rash is polymorphic; the typical element is papules, which are accompanied by itching.

The mechanism looks like this: the body mounts an autoimmune reaction to an unidentified epidermal neoantigen produced by basal layer keratinocytes. T lymphocytes migrate into the skin; their substances destroy basement membranes and trigger apoptosis of basal keratinocytes.

Figures: in Russia in 2012, prevalence among adults aged 18 and older was 11.3 per 100,000 people. The peak occurs at ages 30–60; in children the disease occurs in 5% of cases. Lichen planus is not contagious. The prognosis is usually reassuring: the skin form often resolves on its own in about 9–18 months, while oral involvement may last several years.

How lichen planus looks on the skin

The typical form is flat papules 2–5 mm in diameter with a central depression, pinkish-red with a violet or lilac hue. Peeling is minor, and the scales separate with difficulty. When large nodules are smeared with oil, a reticular pattern appears — the Wickham striae sign.

The eruptions group into rings, garlands, and lines. Favorite sites are the flexor surfaces of the limbs, the trunk, the genitalia, and often the oral mucosa. Itching may be intense but is not always present: in some people the rash causes almost no discomfort. The elements are symmetrical, with clear borders, appear at sites of skin injury, and sometimes form blisters or erosions. On dark skin, redness is harder to recognize. Less commonly, patches of hair loss appear on the head, nails become uneven with grooves, and ring-shaped violet or white spots appear on the penis.

Lichen planus in the mouth: signs

Whitish areas appear in the mouth on the gums, tongue, or inner side of the cheeks. They look like bluish-white spots or nodules that form a lacy network, are located on the sides of the tongue, on the cheeks and gums, and gradually enlarge. Some people feel burning and tingling while eating and drinking; others feel nothing.

Additional symptoms are dry mouth and a metallic taste. Sometimes painful ulcers form. Ulcers in the mouth that persist for a long time can progress to cancer.

Possible causes and factors associated with the disease

The exact cause is unknown. Allergic and immune reactions are discussed. Risk factors include contact with certain medications, dyes, and chemicals: gold, antibiotics, arsenic, iodides, chloroquine, quinacrine, quinine, phenothiazines, diuretics. A second factor is diseases such as hepatitis C.

When the rash is caused by a medication, it resolves after the medication is discontinued.

How it differs from other types of lichen

The word "lichen" is used for various skin diseases, and they are easy to confuse. Psoriasis produces red scaly crusts, more often on the elbows and knees. Pityriasis rosea consists of raised red scaly patches on the body. Lichen sclerosus itches and leaves white areas on the vulva. Ringworm is a ring-shaped red patch anywhere on the body. Eczema is dry, cracked, itchy skin.

• secondary syphilis;
• atopic dermatitis;
• pityriasis rubra pilaris;
• Darier disease;
• psoriasis.

How the diagnosis is made and when to see a doctor

In most cases the diagnosis is made based on the clinical picture. In rare cases histology is needed: a biopsy of a skin element or an oral mucosal element confirms the diagnosis.

You should see a doctor when suspicious eruptions or white areas in the mouth appear, when the elements change appearance, when the condition persists or worsens despite treatment, and also if the dentist advises reviewing medications or treating conditions that trigger the disease.

Lichen planus by itself is not a reason to call an ambulance. 103 or 112 are needed for life-threatening conditions — for example, signs of stroke or heart attack, severe injury, or a sudden deterioration in condition when the person requires emergency care.

This material is for reference and does not replace a doctor's consultation: a specialist makes the decision regarding your situation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer