A 48-year-old man with a 6-month history of widespread violaceous, flat-topped papules and plaques on his lower extremities and genitalia, along with nail dystrophy, is diagnosed with lichen planus. Topical corticosteroids have provided only partial relief. What is the drug of choice for systemic management of this generalized cutaneous lichen planus?

Explanation

## Systemic Treatment of Generalized Cutaneous Lichen Planus **Key Point:** Oral corticosteroids (prednisolone) are the first-line systemic agent for generalized cutaneous lichen planus when topical therapy fails, offering rapid anti-inflammatory response and symptom control. ### Rationale for Oral Prednisolone **High-Yield:** Prednisolone is preferred for systemic lichen planus because: - Rapid onset of action (symptom relief within 1–2 weeks) - Potent immunosuppression targeting T-cell mediated inflammation - Predictable dose–response relationship - Standard dosing: 0.5–1 mg/kg/day, tapered over 8–12 weeks - Effective for both cutaneous and mucocutaneous disease ### Systemic Treatment Algorithm for Lichen Planus ```mermaid flowchart TD A[Generalized LP, topical therapy failed]:::outcome --> B{Extent & severity?}:::decision B -->|Mild-moderate| C[Oral prednisolone 0.5-1 mg/kg/day]:::action B -->|Severe or refractory| D[Oral prednisolone + steroid-sparing agent]:::action C --> E[Taper over 8-12 weeks]:::action D --> F[Add methotrexate or acitretin]:::action E --> G{Response adequate?}:::decision G -->|Yes| H[Continue taper, monitor]:::action G -->|No| I[Consider combination therapy]:::action ``` ### Comparison of Systemic Agents | Agent | Onset | Indication | Limitation | |-------|-------|-----------|------------| | **Prednisolone** | 1–2 weeks | First-line for generalized LP | Long-term use → osteoporosis, infection risk | | Methotrexate | 4–8 weeks | Steroid-sparing, refractory cases | Slower onset; requires monitoring | | Acitretin | 2–4 weeks | Erosive/hypertrophic LP, cutaneous-dominant | Teratogenic; photosensitivity | | Dapsone | 2–4 weeks | Rare; bullous LP variants | Limited evidence; hemolysis risk | ### Why Prednisolone Is First-Line **Clinical Pearl:** Prednisolone achieves rapid control of pruritus and inflammation, allowing time to initiate steroid-sparing agents (methotrexate) if long-term therapy is needed. This prevents cumulative corticosteroid toxicity. **Warning:** ~~Acitretin~~ is NOT first-line for generalized LP in males; it is reserved for erosive or hypertrophic cutaneous variants and is contraindicated in women of childbearing potential due to teratogenicity. **Mnemonic:** **PACED** — Prednisolone (first-line), Acitretin (erosive), Calcineurin inhibitors (steroid-sparing), Etretinate (historical), Dapsone (rare). ### Dosing & Monitoring 1. **Initial:** Prednisolone 0.5–1 mg/kg/day (typically 30–40 mg) for 2–4 weeks 2. **Taper:** Reduce by 5–10 mg every 1–2 weeks over 8–12 weeks 3. **Monitoring:** CBC, renal function, glucose; bone density if >3 months therapy 4. **Adjuncts:** PPI for GI protection; calcium + vitamin D for bone health [cite:Inamadar & Palit IADVL Textbook of Dermatology 5e; Harrison 21e Ch 325]