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Acral Lichen Planus: What You Need to Know

What is Acral Lichen Planus?

Acral lichen planus (ALP) is a localized form of lichen planus that primarily affects the distal (far‑end) parts of the body—especially the hands, feet, fingers, and toes. Like classic lichen planus, ALP is an immune‑mediated inflammatory disease that produces flat‑topped, violaceous (purple‑red) papules and plaques. However, the lesions are usually confined to the acral surfaces and may be accompanied by scaling, hyperkeratosis (thickened skin), or painful erosions.

The condition is considered chronic, meaning it can persist for months to years, and it often follows a relapsing‑remitting pattern. While ALP itself is not life‑threatening, it can significantly affect quality of life because of itching, pain, and cosmetic concerns.

Common Causes

The exact trigger for acral lichen planus is unknown, but several factors are thought to initiate or worsen the immune response. Below are the most frequently cited associations (note that many patients have no identifiable cause).

• Autoimmune dysregulation: An abnormal T‑cell response attacks basal keratinocytes.
• Medications: Certain drugs—especially β‑blockers, thiazide diuretics, non‑steroidal anti‑inflammatory drugs (NSAIDs), and antimalarials—have been linked to lichen planus‑like eruptions.
• Viral infections: Hepatitis C virus (HCV) infection is a well‑documented risk factor for classic lichen planus and may also predispose to acral disease.
• Dental amalgam or metal exposure: Contact hypersensitivity to nickel, gold, or mercury can trigger localized lesions.
• Genetic predisposition: Family clustering suggests a hereditary component, though specific genes remain under investigation.
• Stress and hormonal changes: Physical or emotional stress can exacerbate the immune reaction.
• Cutaneous trauma (Koebner phenomenon): Scratches, pressure, or repeated friction on the hands or feet may lead to new lesions.
• Systemic diseases: Autoimmune thyroid disease, lupus erythematosus, and inflammatory bowel disease have been reported alongside lichen planus.
• Insect bites or allergic reactions: Local irritation can act as a nidus for Koebnerization.
• Smoking: Some studies associate tobacco use with a higher prevalence of lichen planus.

Associated Symptoms

Acral lichen planus rarely occurs in isolation. Patients often notice other skin or mucosal changes, including:

• Intense pruritus (itching) that worsens at night.
• Painful burning or stinging, especially when lesions become erosive.
• White, lacy lines on the oral mucosa (Wickham’s striae) if oral lichen planus is concurrent.
• Nail changes – longitudinal ridging, pitting, or onycholysis (nail detachment).
• Hyperpigmentation or post‑inflammatory dyspigmentation after lesions resolve.
• Secondary bacterial or fungal infection of broken skin.
• Rarely, joint pain (arthralgia) if a systemic autoimmune process is present.

When to See a Doctor

Most cases of ALP can be managed by a dermatologist, but prompt medical evaluation is warranted when any of the following appear:

• Lesions spread beyond the hands or feet or involve the scalp, genitalia, or oral cavity.
• Severe pain or itching that interferes with sleep, work, or daily activities.
• Signs of infection – increased redness, warmth, pus, or fever.
• Rapidly enlarging ulcerations or blisters.
• Persistent lesions that do not improve after 4–6 weeks of over‑the‑counter skin care.
• Any concern for skin cancer, especially in patients with a history of chronic sun exposure.

Early assessment helps confirm the diagnosis, rule out mimicking conditions, and start treatment before complications develop.

Diagnosis

Diagnosing acral lichen planus usually involves a combination of clinical examination and targeted tests.

1. Clinical Evaluation

• Visual inspection: Dermatologists look for the classic “6‑P” signs—purplish hue, planar (flat‑topped) papules, pruritic, polygonal shape, and prominence on flexor surfaces.
• Distribution pattern: Lesions are confined to acral sites; symmetrical involvement of both hands/feet is typical.
• Koebner phenomenon: New lesions may appear at sites of trauma.

2. Skin Biopsy

A 4‑mm punch biopsy of an active lesion is the gold standard. Histology often shows:

• Band‑like lymphocytic infiltrate at the dermal‑epidermal junction.
• Basal cell degeneration (Civatte bodies).
• Hyperkeratosis and saw‑tooth rete ridges.

These findings help differentiate ALP from psoriasis, eczema, or palmoplantar keratoderma.

3. Laboratory Tests (optional)

• Hepatitis C antibody and RNA testing.
• Autoimmune panels (ANA, anti‑thyroid antibodies) if systemic disease is suspected.
• Complete blood count (CBC) and metabolic panel if oral or nail involvement is extensive.

4. Dermoscopy

Non‑invasive dermoscopic examination can reveal Wickham’s striae (white lines) and vascular patterns, supporting a clinical diagnosis without a biopsy in some cases.

Treatment Options

Therapy aims to lessen inflammation, control itching, prevent scarring, and improve function. Treatment is individualized based on severity, extent, patient age, and comorbidities.

Topical Therapies

• High‑potency corticosteroids: Clobetasol propionate 0.05% ointment applied once daily for 2–4 weeks, then tapered. Reduces inflammation quickly.
• Calcineurin inhibitors: Tacrolimus 0.1% ointment or pimecrolimus 1% cream—useful for steroid‑sparing, especially on thin skin or when long‑term treatment is needed.
• Vitamin D analogues: Calcipotriene 0.005% cream can help in mild cases or in combination with steroids.
• Topical retinoids: Tazarotene 0.05% cream may be considered for hyperkeratotic lesions, but can cause irritation.

Systemic Medications

Reserved for moderate‑to‑severe or refractory disease.

• Oral corticosteroids: Prednisone 0.5 mg/kg daily for a short burst (≤2 weeks) followed by a taper.
• Antimalarials: Hydroxychloroquine 200–400 mg daily—effective for mucocutaneous lichen planus; regular ophthalmologic monitoring is required.
• Immunosuppressants: Methotrexate (15–25 mg weekly) or azathioprine (1–2 mg/kg daily) for chronic cases.
• Biologic agents: Mycophenolate mofetil or newer IL‑17/IL‑23 inhibitors have shown promise in recalcitrant lichen planus, though data are limited.

Phototherapy

Narrow‑band UVB (NB‑UVB) three times weekly can improve widespread lesions, but the acral location (hands/feet) often limits exposure. Photochemotherapy (PUVA) may be used under specialist supervision.

Physical and Home Measures

• Moisturizers: Thick, fragrance‑free emollients (e.g., petroleum jelly, ceramide creams) applied after bathing to restore barrier function.
• Cold compresses: Reduce acute itching or burning.
• Antihistamines: Oral second‑generation agents (cetirizine, loratadine) for daytime itch; diphenhydramine at night if sleep is disturbed.
• Protective footwear: Soft, breathable shoes and cushioned insoles to decrease friction and trauma.
• Gentle nail care: Trim nails straight across; avoid aggressive filing that may induce Koebnerization.

Follow‑up

Patients should be re‑evaluated every 4–6 weeks initially, then every 3–6 months once stable. Long‑term monitoring is important because lichen planus can evolve into squamous cell carcinoma, particularly in oral or genital sites (rare in acral disease but still prudent).

Prevention Tips

While ALP cannot always be prevented, certain strategies may reduce the risk of flare‑ups or lessen severity:

• Avoid known triggers: Discuss medication lists with your physician; ask about alternatives to β‑blockers or thiazides if you have a history of lichen planus.
• Protect acral skin from trauma: Wear padded gloves for manual work, use cushioned soles, and keep nails trimmed.
• Maintain skin hydration: Apply emollient at least twice daily, especially after washing.
• Limit sun exposure: Although acral sites are less sun‑exposed, overall UV protection lowers the risk of other skin conditions that could mimic or aggravate lichen planus.
• Manage stress: Regular exercise, mindfulness, or counseling can modulate immune function.
• Screen for hepatitis C: If you have risk factors (e.g., past IV drug use, blood transfusions pre‑1992), get tested.
• Quit smoking: Smoking cessation improves overall immune balance.
• Regular dental check‑ups: Early detection of oral lichen planus prevents progression.

Emergency Warning Signs

Key Takeaways

Acral lichen planus is a chronic, immune‑mediated skin disorder that primarily affects the hands and feet. Though not life‑threatening, it can cause significant discomfort, functional limitation, and cosmetic concerns. Prompt diagnosis—usually confirmed by skin biopsy—and individualized treatment (topical steroids, systemic agents, and supportive skin care) are essential for symptom control. Patients should stay vigilant for infection, rapid lesion changes, or systemic signs, and contact a healthcare professional promptly if these occur.

References:

• Mayo Clinic. “Lichen planus.” Updated 2023. https://www.mayoclinic.org
• National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). “Lichen Planus.” 2022. https://www.niams.nih.gov
• Cleveland Clinic. “Treatment options for lichen planus.” 2024. https://my.clevelandclinic.org
• World Health Organization. “Hepatitis C Fact Sheet.” 2023. https://www.who.int
• Dermatology literature: Zhou Y, Tang J. “Acral lichen planus: clinical features and management.” *Journal of Dermatologic Treatment* 2021;32(5):567‑575.

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