What is the next step in treating a patient with a rash on the forehead that did not respond to Triamcinolone (Triamcinolone) 1% and is currently taking Terbinafine (Terbinafine) 250mg once daily?

Management of Forehead Rash Unresponsive to Triamcinolone in Patient on Terbinafine

Escalating to clobetasol propionate 0.05% once daily for 15 days is appropriate for a forehead rash that failed triamcinolone 1%, while continuing terbinafine 250mg daily for the underlying fungal infection. 1

Rationale for Topical Corticosteroid Escalation

The forehead rash likely represents a dermatological adverse reaction to terbinafine, which occurs in approximately 23% of patients taking oral terbinafine. 2 Common dermatological events include rash, pruritus, urticaria, or eczema. 2

Why Clobetasol is the Appropriate Next Step

• Triamcinolone 0.1% is a mid-potency (Class IV-V) topical corticosteroid, and its failure indicates the need for a more potent agent. 2
• Clobetasol propionate 0.05% is a super-high potency (Class I) topical corticosteroid, making it the logical escalation for inflammatory dermatoses unresponsive to mid-potency steroids. 3
• The 15-day duration is appropriate to avoid skin atrophy and other adverse effects associated with prolonged super-potent corticosteroid use on facial skin. 3

Critical Safety Consideration: Monitor for Serious Cutaneous Reactions

You must remain vigilant for signs of severe hypersensitivity reactions, as terbinafine has been associated with rare but serious dermatological adverse events:

• Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported with terbinafine use. 2, 1
• Acute generalized exanthematous pustulosis (AGEP) can occur, typically presenting 1 week after terbinafine initiation with pustular rash extending from one area to multiple body regions. 3
• Hypersensitivity syndrome reaction involving cutaneous eruption, fever, lymphadenopathy, and hepatic dysfunction can develop after 4-5 weeks of therapy. 4

Red Flags Requiring Immediate Terbinafine Discontinuation

• Mouth sores, blistering, or peeling of skin 5
• Swelling of face, lips, tongue, or throat 5
• Difficulty swallowing or breathing 5
• Pustular transformation of the rash 3
• Systemic symptoms (fever, lymphadenopathy) 4

Continuing Terbinafine: When It's Safe

Continuing terbinafine 250mg daily is appropriate if the rash represents a mild, localized dermatological reaction without systemic involvement. 2, 1

Standard Terbinafine Monitoring Requirements

• Baseline and periodic liver function tests are essential, particularly given that concurrent hepatitis can occur with terbinafine-induced rashes. 3
• The incidence of serious adverse events with terbinafine is only 0.04%, making continuation reasonable for mild localized reactions. 2
• Terbinafine should be continued for the full prescribed duration: 6 weeks for fingernail onychomycosis or 12 weeks for toenail onychomycosis. 1, 5

When to Discontinue Terbinafine

• Development of new or worsening lupus erythematosus symptoms (erythema, scaling, loss of pigment, photosensitivity) 5
• Persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, or pale stools 5
• Any signs of severe cutaneous adverse reactions as outlined above 5

Alternative Diagnosis Consideration

If the forehead rash represents seborrheic dermatitis rather than a drug reaction, terbinafine may actually provide therapeutic benefit, as it has demonstrated efficacy in treating multi-site seborrheic dermatitis at 250mg daily for 6 weeks. 6 However, this would typically involve non-exposed sites like the scalp and sternum rather than isolated forehead involvement. 6

Practical Management Algorithm

1. Assess for systemic symptoms (fever, lymphadenopathy, mucosal involvement, hepatic symptoms) 4, 3
2. If systemic symptoms present: Discontinue terbinafine immediately and consider hospitalization 3
3. If localized rash only: Check liver function tests 3
4. If LFTs normal and no red flags: Continue terbinafine and apply clobetasol 0.05% once daily for 15 days 1, 3
5. Re-evaluate in 1 week: If rash worsens or systemic symptoms develop, discontinue terbinafine 5
6. If rash improves: Complete terbinafine course and taper clobetasol after 15 days 1