A 52-year-old woman presents with a 6-week history of painful erosions on the buccal mucosa and gingiva, along with a reticular pattern of white lines. Examination reveals violaceous papules on the flexural surfaces of both wrists and ankles. A biopsy confirms lichen planus. She reports no systemic symptoms and her liver function tests are normal. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has biopsy-confirmed lichen planus with erosive oral involvement (painful erosions on buccal mucosa and gingiva) and cutaneous manifestations. Erosive oral lichen planus is a significant subset requiring aggressive management because of pain, functional impairment, and potential malignant transformation risk. ## Management Hierarchy for Lichen Planus | Presentation | First-Line Management | Second-Line | |---|---|---| | **Non-erosive oral LP** | Topical corticosteroids (triamcinolone) | Topical tacrolimus | | **Erosive oral LP** | Systemic corticosteroids ± topical agents | Systemic retinoids, azathioprine | | **Cutaneous LP (localized)** | Topical corticosteroids | Intralesional corticosteroids | | **Cutaneous LP (generalized/severe)** | Systemic corticosteroids or retinoids | Azathioprine, cyclosporine | ## Why Systemic Corticosteroids Here **Key Point:** Erosive oral lichen planus is considered a "severe" variant and is one of the few indications for systemic corticosteroid therapy in lichen planus. 1. **Erosive disease = systemic therapy**: Topical agents alone are insufficient for erosive oral lesions because: - Erosions are painful and functionally disabling - Topical corticosteroids have limited penetration into deep erosive lesions - Risk of secondary infection and scarring is higher 2. **Dose rationale**: Prednisolone 0.5–1 mg/kg/day is standard for erosive oral LP, typically given for 4–6 weeks with gradual taper. 3. **Cutaneous lesions are mild**: The violaceous papules on flexural surfaces are non-erosive and do not independently require systemic therapy; they often respond to topical corticosteroids or resolve as oral disease improves. **High-Yield:** Erosive oral lichen planus + cutaneous LP = **systemic corticosteroids** is the standard of care. ## Why Other Options Are Not First-Line **Clinical Pearl:** Topical tacrolimus is a steroid-sparing alternative for **non-erosive** oral LP or as adjunctive therapy in erosive disease, but it is not monotherapy for erosive lesions. It has slower onset and requires longer contact time. **Warning:** Hepatitis C screening is recommended as part of baseline workup in lichen planus (especially in endemic regions), but this patient's normal LFTs and absence of systemic symptoms make it a screening step, not an urgent management priority. It does not address the acute erosive oral disease. Systemic retinoids (acitretin) are reserved for: - Cutaneous LP unresponsive to corticosteroids - Erosive oral LP refractory to corticosteroids - Not first-line for erosive disease. ## Summary Algorithm ```mermaid flowchart TD A[Lichen Planus confirmed]:::outcome --> B{Erosive oral involvement?}:::decision B -->|Yes| C[Systemic corticosteroids<br/>prednisolone 0.5-1 mg/kg/day]:::action B -->|No| D{Localized cutaneous?}:::decision D -->|Yes| E[Topical corticosteroids]:::action D -->|No| F[Systemic corticosteroids<br/>or retinoids]:::action C --> G[Taper over 4-6 weeks]:::action C --> H[Add topical tacrolimus<br/>as adjunct]:::action ```