What is the appropriate management for a patient presenting with a violaceous rash?

Management of Violaceous Rash

For a patient presenting with a violaceous rash, initiate high-potency topical corticosteroids (clobetasol 0.05% or fluocinonide 0.05%) or tacrolimus 0.1% ointment immediately, as this presentation is characteristic of immune checkpoint inhibitor-related lichen planus or lichenoid disease. 1

Initial Clinical Assessment

When evaluating a violaceous rash, focus on these specific features:

• Distribution pattern: Look for violaceous (dark red/purple) papules and plaques without scale over the trunk and extremities 1
• Associated symptoms: Assess for significant pruritus, which is characteristic 1
• Mucosal involvement: Examine for erosions and striae (white lines intersecting) in the oral and vulvar mucosa 1
• Medication history: Determine if the patient is receiving immune checkpoint inhibitors (ICIs), as onset typically occurs 6-12 weeks after initiation 1
• Systemic features: Rule out polymyositis, which can present with characteristic violaceous rash on hands, elbows, and knees along with proximal muscle weakness 2

First-Line Topical Treatment

Apply high-potency topical corticosteroids to all affected areas regardless of severity grade: 1

• Clobetasol 0.05% (cream or ointment) OR
• Fluocinonide 0.05% (cream or ointment) OR
• Tacrolimus 0.1% ointment as an alternative 1

Formulation selection based on location: 1

• Gel for mucosal disease
• Solution for scalp disease
• Cream/lotion/ointment for all other affected areas

Adjunctive Symptomatic Management

For pruritus control, add: 1

• Oral antihistamines: Cetirizine, loratadine, or fexofenadine for grade 2/3 pruritus 1
• Urea or polidocanol-containing lotions for direct soothing effects 3, 1
• Avoid topical antihistamines due to contact dermatitis risk 3

Systemic Therapy Considerations

If topical therapy is insufficient or disease is extensive: 1

• Oral prednisone: Consider for moderate-to-severe cases 1
• Narrow-band UVB phototherapy: Recommended if available 1
• Alternative immunomodulators for refractory cases: Hydroxychloroquine, azathioprine, methotrexate, or mycophenolate mofetil 1

ICI-Related Management Decisions

Do not automatically discontinue ICIs for lichenoid reactions: 1

• Most cases (81%) respond to topical steroids alone 1
• Continue ICI therapy while managing dermatologic toxicity 1
• Only discontinue for grade 4 reactions or if life-threatening 1

Critical Pitfalls to Avoid

Do not delay treatment while awaiting biopsy confirmation - the clinical presentation of violaceous papules and plaques is sufficiently characteristic to begin therapy 1

Avoid alcohol-containing preparations - these worsen xerosis and can exacerbate symptoms 1

Do not use OTC anti-acne medications - lichenoid eruptions are inflammatory, not seborrheic, and acne treatments will worsen the condition 1

Avoid hot water and excessive soap use - these remove natural skin lipids and worsen barrier dysfunction 1, 3

When to Escalate Care

Refer to dermatology if: 1

• Diagnosis remains unclear after initial evaluation
• Grade 2 rash worsening despite topical intervention 1
• Mucosal involvement is extensive 1
• No response to high-potency topicals within 2 weeks 1
• Blistering covering ≥1% body surface area develops 1

Follow-Up Strategy

Reassess at 2 weeks or sooner if symptoms worsen: 1

• If improving, continue current regimen and taper steroids gradually
• If stable or worsening, escalate to systemic therapy 1
• Monitor for secondary infection, particularly with Staphylococcus aureus 1