OVERVIEW

What is lichen planus?

Lichen planus is a complex, itchy, inflammatory rash that causes purplish-red, polygonal, flat papules on the skin (the skin appears dry and ridged like lichen growing on a tree trunk, hence the name), often accompanied by pain.

Lichen planus can affect the skin anywhere on the body, including the external genitalia, scalp, fingernails/toenails, and oral mucosa (the pink, moist "skin" inside the mouth).

Localized lichen planus is primarily treated with corticosteroid injections, while generalized lichen planus is mainly treated with oral medications or phototherapy. Most patients can expect a good quality of life after treatment.

What are the types of lichen planus?

The main types include cutaneous lichen planus, genital lichen planus, oral lichen planus, and lichen planopilaris.

Is lichen planus common?

Data on the incidence of lichen planus is limited. It is estimated that less than 1% of the population has cutaneous lichen planus, 0.5%–2% have genital lichen planus, 1%–3% have oral lichen planus, and lichen planopilaris is even rarer.

SYMPTOMS

What are the common manifestations of lichen planus?

Lichen planus can cause different symptoms depending on the affected body part.

• Cutaneous lichen planus: When affecting the skin, it typically causes shiny, flat red or purple spots, often appearing on the wrists, arms, or legs, though other areas may also be involved. These lesions are usually very itchy and may darken during healing. The classic presentation of cutaneous lichen planus can be described by the "4 Ps":

  • Pruritic (itchy)

  • Purple (actually pale purplish-red)

  • Polygonal

  • Papules or plaques

• Nail lichen planus: When nails are affected, mild cases may show slight atrophy, while severe cases can lead to complete nail loss. The disease process primarily occurs in the nail bed.

• Lichen planopilaris (scalp lichen planus): Patients experience patchy hair loss with follicular keratotic papules. Without timely treatment, it may progress to scarring alopecia. Once hair follicles are destroyed, regrowth is impossible.

• Oral lichen planus: Mucosal lichen planus may occur alone or alongside cutaneous lichen planus. It may present as lace-like Wickham's striae (fine white lines on the surface of papules or plaques), particularly noticeable on the buccal mucosa, or as papular, atrophic, or erosive lesions.

  Erosive mucosal disease is often painful and may lead to secondary complications (e.g., superficial candidiasis). Patients often report persistent loss of appetite due to pain while eating.

• Genital lichen planus: In males, it appears as purplish-red papules on the glans penis, while in females, lesions typically occur on the vulva. Vulvovaginal-gingival syndrome is an erosive form affecting the vulva, vestibule, vagina, and oral epithelium, which is highly resistant to treatment.

  Although all three areas may be involved, lesions may not appear simultaneously. The gingival epithelium is commonly affected, but erosions, white plaques, or lace-like reticulated patterns may also appear on the buccal mucosa, tongue, or palate.

• Esophageal lichen planus: It may involve the esophagus, with or without symptoms like dysphagia or odynophagia. Endoscopic findings may include pseudomembranes, friable and inflamed mucosa, submucosal papules, lace-like white plaques, erosions, strictures, and other abnormalities.

  Patients often have concurrent oral, genital, or cutaneous lichen planus. The prevalence of esophageal lichen planus remains unknown.

• Lichen planus of the ear: The stratified squamous epithelium of the external ear canal and tympanic membrane can be affected. Common clinical features include erythema, induration, and stenosis of the ear canal; thickened tympanic membrane; otorrhea; and hearing loss.

  Lichen planus may or may not be present in other body parts. Further research is needed to determine the prevalence of this manifestation.

CAUSES

How is lichen planus contracted?

The exact cause of lichen planus is currently unknown. Many factors may contribute to its onset, possibly related to neuropsychiatric factors, endocrine factors, systemic disease factors, genetic factors, viral infections, or autoimmunity.

Who is most commonly affected by lichen planus?

Lichen planus most frequently occurs in adults and is rare in children.

Is lichen planus contagious?

No.

Is lichen planus hereditary?

Since the onset of lichen planus is considered an autoimmune response, there may be some genetic predisposition.

DIAGNOSIS

How is Lichen Planus Diagnosed?

The clinical evaluation of patients with suspected cutaneous lichen planus includes patient history and physical examination. The doctor will ask the patient the following questions:

• Medication history: Including drugs that may induce lichen planus.

• Presence of skin itching: A common symptom of cutaneous lichen planus.

• Oral or genital erosions or pain: Findings suggestive of concomitant mucosal lichen planus.

• Dysphagia or painful swallowing: Findings suggestive of esophageal involvement.

The physical examination should include an inspection of the entire skin surface (including the scalp), as well as the oral cavity and external genitalia. A thorough and detailed examination helps assess the extent and severity of lesions and may aid in identifying other affected areas.

• When the skin exhibits itchy, purplish-red, polygonal papules or plaques;

• Lines or ridges form on the fingernails or toenails;

• Pink, moist "skin" appears inside the mouth, vagina, or other organs, accompanied by painful red ulcers or white lace-like lesions, medical attention should be sought immediately.

Healthcare providers can generally determine whether you have lichen planus by understanding these symptoms and performing a physical examination. They may also collect a small skin sample for biopsy to confirm the diagnosis.

What Diseases Can Lichen Planus Be Confused With? How to Differentiate Them?

• Lichenoid drug eruption: The skin manifestations of lichenoid drug eruption are very similar to those of idiopathic lichen planus. The patient's medication history and skin biopsy can help distinguish lichenoid drug eruption from lichen planus.

• Chronic graft-versus-host disease: A history of hematopoietic cell transplantation can aid in the diagnosis.

• Lichen sclerosus: Lichen sclerosus can cause structural distortion and labial adhesions, but unlike vulvar lichen planus, it rarely involves the vagina. Its typical manifestations include white atrophic papules or plaques on the vulva, which may appear hemorrhagic, purpuric, hyperkeratotic, bullous, or erosive.

• Oral squamous cell carcinoma: Oral squamous cell carcinoma may present as erythematous or white patches, ulcers, or exophytic masses. A biopsy can aid in diagnosis.

A definitive diagnosis of the specific condition should be made by a specialist. Self-medication should be avoided to prevent delaying treatment.

TREATMENT

Which department should I visit for lichen planus?

For initial consultation of lichen planus, the dermatology department is recommended. If accompanied by oral mucosal lesions or gingivitis, patients may also consult the stomatology department.

Can lichen planus heal on its own?

Most cases of cutaneous lichen planus resolve within 1–2 years, with treatment focusing on accelerating symptom relief and controlling itching.

Lichen planus affecting the oral cavity, genitals, scalp, or nails often takes longer to resolve. Particularly for oral and genital (especially erosive) lichen planus, patients face increased risks of anxiety and depression, which can significantly impair quality of life, necessitating active treatment.

What are the treatment options for lichen planus?

Treatment varies depending on the affected body part and symptom severity, and may include:

• Corticosteroids: Typically in ointment, cream, or gel form to reduce inflammation and promote skin healing, such as fluocinonide or 0.05% betamethasone dipropionate.
• Calcineurin inhibitors: Such as tacrolimus.
• Anesthetics and pain relievers: Especially for patients with oral or genital ulcers.
• Medications to reduce inflammation or promote skin healing.
• Phototherapy: Usually involving ultraviolet light.

Some patients may need to try multiple medications to find the most effective one.

What medications can be used for lichen planus?

• Cutaneous lichen planus is primarily treated with topical corticosteroids like fluocinonide or 0.05% betamethasone dipropionate, or injectable triamcinolone acetonide.
• Oral retinoids can also significantly improve symptoms.
• Oral antihistamines like diphenhydramine may help control itching.
• Genital, oral, or scalp lichen planus is mainly treated with topical corticosteroids or calcineurin inhibitors like tacrolimus. Vaginal lichen planus may require suppositories.
• For pain management, NSAIDs (e.g., ibuprofen), acetaminophen, or topical anesthetics like 2% viscous lidocaine solution or gel can be used.

Is hospitalization required for lichen planus?

Generally, no. However, severe cases involving infection, anxiety, depression, or significant quality-of-life impairment should seek professional medical help.

Can lichen planus recur?

Lichen planus often resolves spontaneously within 1–2 years, but recurrence is possible. Vulvovaginal and oral lichen planus tend to have prolonged, stubborn courses and may even be difficult to cure.

DIET & LIFESTYLE

What should patients with lichen planus pay attention to in daily life?

• Take good care of your skin. Gently wash and dry your skin when bathing, and try to avoid scratching itchy skin, as this may increase the risk of infection and worsen lichen planus.

• For oral lichen planus, be sure to care for your teeth and gums. Brush twice daily with a soft-bristled toothbrush and floss every day. Poor oral hygiene can aggravate lichen planus and may lead to other dental and gum problems.

• Patients with oral lichen planus should quit smoking or using smokeless tobacco and reduce intake of acidic, salty, spicy, hot, sharp, or rough-textured foods.

What dietary precautions should lichen planus patients take?

• Patients with oral lichen planus should quit smoking and reduce intake of acidic, salty, spicy, hot, sharp, or rough-textured foods.

• When cooking, use less salt, oil, and high-sodium seasonings. Avoid pickled vegetables and meats.

• Do not rely solely on refined grains. Replace some staple foods with whole grains, legumes, potatoes, or pumpkin.

• Balance meat and vegetables in meals. Prioritize white meats like chicken, duck, and fish, and limit fatty meats. Eggs and milk are important sources of protein and other nutrients.

• Vegetarians can eat more beans and bean products to supplement protein.

• Increase intake of fresh fruits and vegetables.

• Avoid alcohol as much as possible.

PREVENTION

Can lichen planus be prevented?

The cause of lichen planus is currently unknown, and it cannot be prevented.