Cutaneous lichen planus is a subtype of lichen planus, a chronic inflammatory autoimmune condition, specifically affecting the skin. It presents as itchy, flat-topped, polygonal, purplish papules with a network of fine white lines (Wickham’s striae) on the surface. Common sites include the wrists, forearms, ankles, shins, and lower back, but it can appear anywhere.

Key Features:

• Appearance: Shiny, violet-red papules (2-10 mm), often with a scaly surface; may cluster or form lines (Koebner phenomenon).
• Symptoms: Intense itching; rarely painful unless scratched excessively.
• Variants:
• Hypertrophic: Thick, warty plaques, often on shins.
• Atrophic: Thinned skin after lesions resolve.
• Annular: Ring-shaped lesions, often on genitals or trunk.
• Linear: Lesions along scratch marks or skin lines.
• Course: Lesions may resolve in 1-2 years, often leaving dark spots (post-inflammatory hyperpigmentation), especially in darker skin tones.

Causes/Triggers:

• Unknown exact cause; likely autoimmune.
• Triggers: Stress, medications (e.g., beta-blockers, NSAIDs), hepatitis C, or skin trauma.

Diagnosis:

• Clinical exam by a dermatologist.
• Skin biopsy if unclear (shows characteristic inflammation at the dermal-epidermal junction).
• Rule out similar conditions (e.g., psoriasis, eczema, tinea versicolor).

Treatment:

• Mild cases:
• Topical corticosteroids (e.g., clobetasol, betamethasone) to reduce inflammation and itching.
• Topical calcineurin inhibitors (e.g., tacrolimus) for sensitive areas.
• Severe/widespread cases:
• Oral corticosteroids (e.g., prednisone) for short-term control.
• Phototherapy (narrowband UVB).
• Oral retinoids (e.g., acitretin) or immunosuppressants (e.g., methotrexate) in resistant cases.
• Symptom relief:
• Antihistamines (e.g., cetirizine) for itching.
• Moisturizers to prevent dryness.
• Monitoring: Regular follow-ups, as chronic cases may scar or cause pigmentation changes.

Management:

• Avoid scratching to prevent worsening (Koebner phenomenon).
• Identify and avoid triggers (e.g., stress, certain drugs).
• Protect skin from trauma or irritation.

Cutaneous lichen planus is typically self-limiting but can be distressing due to itching and appearance.

Disclaimer: owerl is not a doctor; please consult one.