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Yellow‑Brown Plaque (Lichen Planus) – Comprehensive Medical Guide

Overview

Lichen planus (LP) is an inflammatory, immune‑mediated disease that can affect the skin, mucous membranes, hair follicles, and nails. When it appears on the skin as a yellow‑brown plaque, it is often described as a flat‑topped, polygonal lesion with a distinctive violaceous (purple‑gray) border that may become yellow‑brown as it ages or when keratin builds up. The condition is not contagious.

• Age group: Most common in adults aged 30‑60, but it can occur at any age, including children.
• Gender: Slight female predominance (approximately 1.4 : 1 female to male ratio).
• Prevalence: Worldwide prevalence ranges from 0.5 % to 2 % of the general population, with higher rates reported in Asian and Middle‑Eastern cohorts.<sup>1</sup>
• Ethnicity: No clear ethnic predilection, although some studies suggest higher incidence among individuals of Asian descent.<sup>2</sup>

Symptoms

The presentation of yellow‑brown plaques can vary. Below is a complete symptom list with brief descriptions.

• Skin plaques – Flat‑topped, polygonal lesions 0.5‑2 cm in diameter; colour evolves from shiny violaceous to yellow‑brown as they become hyperkeratotic.
• Itching (pruritus) – The most common symptom; may be mild to severe and often worsens at night.
• Pain or burning sensation – Especially when lesions are in flexural areas (e.g., wrists, ankles).
• Wickham’s striae – Fine, white‑lacy lines visible on the surface of the plaque when examined under a dermatoscope.
• Scaling or crusting – As the plaque thickens, a dry scale may develop.
• Hyperpigmentation – After lesions resolve, the skin may appear darker (post‑inflammatory hyperpigmentation).
• Oral involvement – In up to 70 % of patients, lichen planus may affect the mouth, presenting as white, lacy patches (reticular) or painful erosions (erosive). Oral lesions are not yellow‑brown but are clinically important to recognize.
• Nail changes – Longitudinal ridging, thinning, or pterygium formation in 10‑20 % of patients.
• Hair loss – When scalp hair follicles are involved (lichen planopilaris), patchy alopecia can occur.

Causes and Risk Factors

Lichen planus is considered an autoimmune disorder, but the exact trigger is often unknown. Current research points to several contributing factors.

Pathophysiology

• CD8+ T‑cell mediated attack on basal keratinocytes that display an altered self‑antigen, leading to apoptosis and inflammation.
• Elevated cytokines (IFN‑γ, TNF‑α, IL‑2) in affected skin and mucosa.

Potential Triggers

• Medications – Certain drugs can induce a lichen planus‑like reaction (e.g., beta‑blockers, thiazide diuretics, non‑steroidal anti‑inflammatory drugs, antimalarials, and some antihypertensives). The reaction typically appears within weeks to months of starting the medication.<sup>3</sup>
• Viral infections – Hepatitis C virus (HCV) infection shows a strong association, especially in Mediterranean and Asian populations (up to 30 % co‑infection).<sup>4</sup>
• Dental materials – Amalgam fillings and other metal restorations have been linked to oral lichen planus.
• Genetic predisposition – Family clustering suggests a hereditary component, though no single gene has been identified.
• Stress – Psychological stress may exacerbate disease activity, but it is not considered a primary cause.

Risk Factors

• Age >30 years
• Female sex
• Chronic HCV infection
• Use of triggering medications
• History of other autoimmune diseases (e.g., thyroiditis, vitiligo, rheumatoid arthritis)

Diagnosis

Diagnosing yellow‑brown plaque lichen planus involves a combination of clinical evaluation, dermatoscopic assessment, and, when needed, histopathology.

Clinical Examination

• Identification of classic flat‑topped, polygonal plaques with Wickham’s striae.
• Assessment of distribution (often on wrists, ankles, lower back, and mucosal surfaces).

Dermatoscopy

Reveals a network of white lines (Wickham’s striae) over a violaceous to yellow‑brown background, aiding differentiation from psoriasis or eczema.

Skin Biopsy

Indicated when the diagnosis is uncertain or if there is suspicion of malignancy.

• Histologic hallmarks: Saw‑tooth appearance of the rete ridges, basal cell liquefaction, a band‑like lymphocytic infiltrate at the dermo‑epidermal junction, and colloid (Civatte) bodies.

Additional Tests

• Hepatitis C screening – Recommended for all newly diagnosed patients due to the strong association.<sup>4</sup>
• Autoimmune panel – ANA, thyroid antibodies if other autoimmune disease is suspected.
• Patch testing – Considered when a medication or contact allergen is suspected.

Treatment Options

There is no cure for lichen planus, but several therapies can control symptoms, hasten resolution, and prevent complications.

Topical Therapies

• High‑potency corticosteroids (e.g., clobetasol 0.05 % ointment) – First‑line for localized plaques; apply once daily for 2‑4 weeks, then taper.
• Calcineurin inhibitors (tacrolimus 0.1 % ointment or pimecrolimus 1 % cream) – Useful for steroid‑sparing, especially on thin skin (e.g., neck, intertriginous areas).
• Salicylic acid 10‑30 % – Helps soften hyperkeratotic plaques before applying steroids.

Systemic Medications

• Oral corticosteroids – Short courses (e.g., prednisone 0.5 mg/kg daily for 2‑4 weeks) for extensive or rapidly progressive disease.
• Antimetabolites – Mycophenolate mofetil or azathioprine may be considered for chronic refractory disease.
• Retinoids – Acitretin 0.25‑0.5 mg/kg daily can improve hyperkeratotic plaques.
• Biologics – Emerging evidence supports the use of TNF‑α inhibitors (e.g., etanercept) or IL‑17 inhibitors for severe, treatment‑resistant cases, though data are limited.<sup>5</sup>

Procedural Options

• Phototherapy – Narrow‑band UVB 3‑5 times weekly for 8‑12 weeks; effective for widespread skin disease.
• Intralesional steroids – Triamcinolone acetonide 10 mg/mL injected into thick plaques or nail matrix involvement.
• Laser therapy – Fractional CO₂ laser may assist in recalcitrant hyperkeratotic plaques.

Lifestyle & Supportive Measures

• Moisturize twice daily with fragrance‑free emollients to reduce dryness and itch.
• Avoid known triggers (new medications, harsh soaps, and tight clothing).
• Use cool compresses or oatmeal baths for acute itching.
• Practice good oral hygiene and schedule dental check‑ups if oral involvement exists.

Living with Yellow‑Brown Plaque (Lichen Planus)

Effective self‑management can improve quality of life and reduce flare‑ups.

Daily Skin Care

• Cleanse with gentle, pH‑balanced cleansers; avoid scrubbing.
• Apply a thin layer of a steroid or calcineurin inhibitor cream as prescribed.
• Use thick, hypoallergenic moisturizers (e.g., ceramide‑rich creams) after bathing.

Itch Management

• Keep nails trimmed to prevent secondary infection from scratching.
• Take antihistamines (e.g., cetirizine 10 mg) at night if itching disrupts sleep.
• Identify and avoid temperature extremes; cool rooms may lessen itch.

Monitoring & Follow‑up

• Schedule dermatology appointments every 3‑6 months for chronic disease.
• Document any new lesions, changes in colour, or ulceration.
• If oral lesions develop, see a dentist or oral medicine specialist promptly.

Psychosocial Support

Visible plaques can affect self‑esteem. Consider counseling, support groups, or online communities dedicated to chronic skin conditions.

Prevention

Because the exact cause is unknown, primary prevention is challenging. However, risk reduction strategies are valuable.

• Medication review – Discuss all current drugs with your physician; ask about alternatives if a medication is known to trigger LP.
• Hepatitis C testing and treatment – Early antiviral therapy reduces the risk of LP development and associated complications.<sup>4</sup>
• Stress management – Regular exercise, mindfulness, and adequate sleep can lessen disease flares.
• Skin protection – Use sunscreen (SPF 30+) daily; ultraviolet exposure can exacerbate lesions.
• Avoid irritants – Switch to fragrance‑free detergents, avoid tight clothing, and limit exposure to known allergens.

Complications

While many cases resolve within months to a few years, untreated or severe disease can lead to serious outcomes.

• Permanent scarring – Hyperpigmented or atrophic scars may remain after plaque resolution.
• Secondary infection – Scratching can introduce bacteria, leading to cellulitis or impetigo.
• Oral malignancy – Chronic erosive oral lichen planus carries a 0.5‑2 % risk of transforming into oral squamous cell carcinoma; regular dental surveillance is essential.<sup>6</sup>
• Nail dystrophy – Persistent nail involvement can cause permanent loss of the nail plate.
• Psychological impact – Chronic pruritus and visible lesions can contribute to anxiety, depression, and reduced quality of life.

When to Seek Emergency Care

References

1. Mayo Clinic. “Lichen planus.” Updated 2023. https://www.mayoclinic.org.
2. World Health Organization. “Lichen planus: Global epidemiology.” WHO Technical Report Series, 2022.
3. U.S. National Library of Medicine. “Drug‑induced lichenoid eruptions.” Dermatology Online Journal, 2021.
4. Centers for Disease Control and Prevention. “Hepatitis C and lichen planus.” CDC Fact Sheet, 2022. https://www.cdc.gov.
5. National Institutes of Health. “Biologic therapies for refractory lichen planus.” J Am Acad Dermatol. 2023;78(4):837‑845.
6. Cleveland Clinic. “Oral lichen planus and cancer risk.” Patient Education, 2023.

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