Overview

Lichen planus is a chronic inflammatory skin condition that affects the skin, mucous membranes, hair, and nails. It is characterized by flat-topped, itchy, purple-colored bumps on the skin, and it can also present as painful sores in the mouth or genital areas. Lichen planus is considered an autoimmune disease, where the body’s immune system mistakenly attacks its own cells. Although it is not contagious or cancerous, the condition can cause significant discomfort and cosmetic concerns. Lichen planus commonly affects middle-aged adults but can occur at any age, and both men and women can be affected.

Causes

The exact cause of lichen planus is not completely understood, but it is believed to be an autoimmune reaction where the immune system targets the skin or mucosal cells. Several factors have been associated with the development or worsening of lichen planus, including:

• Autoimmune response: Abnormal immune activity targeting the skin’s keratinocytes is a primary factor.
• Infections: Hepatitis C virus infection has been strongly linked with lichen planus, especially oral and mucosal forms.
• Medications: Certain drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDs), antihypertensives, antimalarials, and beta-blockers, can induce lichen planus-like reactions.
• Dental materials: Dental fillings containing amalgam may trigger oral lichen planus in some individuals.
• Stress: Emotional stress can worsen symptoms in some patients.
• Genetic predisposition: Although not strongly hereditary, some familial cases have been reported.

Symptoms

The symptoms of lichen planus vary depending on the area of the body affected. Common manifestations include:

• Skin symptoms:
  • Flat-topped, polygonal, shiny, violaceous (purple) papules or plaques.
  • Intense itching (pruritus), which is often the most distressing symptom.
  • Commonly affected areas include wrists, ankles, lower back, and forearms.
  • Wickham striae (fine white lines) may be visible on the surface of the lesions.
• Oral lichen planus:
  • White, lacy patches on the inner cheeks, gums, or tongue.
  • May cause burning sensation or pain, especially while eating spicy or acidic foods.
• Genital lichen planus:
  • Painful red or white patches on genital or anal areas.
  • Itching and discomfort are common.
• Nail involvement:
  • Thinning, ridging, and splitting of nails.
  • In severe cases, permanent nail loss can occur.
• Scalp (lichen planopilaris):
  • Patchy hair loss with redness and irritation of the scalp.

Diagnosis

Diagnosis of lichen planus is primarily clinical but may require additional testing to confirm the diagnosis and rule out other conditions:

• Clinical examination: Dermatologists can often diagnose lichen planus by examining the characteristic skin or mucosal lesions.
• Skin biopsy: A small sample of skin is taken and examined under a microscope to confirm the diagnosis, showing typical features like a band-like lymphocytic infiltrate.
• Blood tests: Screening for hepatitis C virus, especially in cases of oral lichen planus.
• Patch testing: May be performed if contact allergies are suspected.
• Direct immunofluorescence: Specialized testing on biopsy samples can help differentiate lichen planus from similar conditions.

Treatment

Treatment of lichen planus aims to relieve symptoms, especially itching and discomfort, and to minimize skin damage. While there is no cure, many patients achieve good symptom control with treatment:

• Topical corticosteroids: First-line treatment for skin and oral lichen planus to reduce inflammation and itching.
• Calcineurin inhibitors: Such as tacrolimus or pimecrolimus, used especially for sensitive areas like the face or genitals.
• Antihistamines: Help reduce itching and improve sleep quality.
• Systemic treatments:
  • Oral corticosteroids for severe or widespread cases.
  • Immunosuppressive agents like methotrexate or azathioprine for resistant cases.
  • Retinoids (like acitretin) may be used in severe cases.
• Phototherapy: Narrowband UVB or PUVA therapy may be effective in widespread or stubborn cases of skin lichen planus.
• Dental care: For oral lichen planus, good oral hygiene and avoiding triggers like spicy foods can help reduce symptoms.
• Treating underlying causes: Managing associated conditions, such as hepatitis C or stopping an offending drug, can lead to improvement.

Prognosis

The prognosis of lichen planus varies depending on its type and severity:

• Skin lichen planus: Often resolves within 6 months to 2 years but may leave behind dark pigmentation (post-inflammatory hyperpigmentation).
• Oral and genital lichen planus: Tend to be more chronic, sometimes persisting for years with periods of flare-ups and remission.
• Nail involvement: Nail damage can be permanent in severe cases if not treated early.
• Hair involvement: Lichen planopilaris can lead to scarring alopecia, causing irreversible hair loss.
• Cancer risk: Long-standing oral lichen planus has a slightly increased risk of developing oral cancer, requiring regular monitoring.

Overall, many cases of lichen planus improve with treatment, especially those limited to the skin. Regular follow-up and early treatment of flare-ups can help manage symptoms effectively and improve quality of life.