What is the management approach for a patient presenting with target lesions suggestive of erythema multiforme (EM)?

Management of Target Lesions in Erythema Multiforme

For patients presenting with target lesions consistent with erythema multiforme, initiate symptomatic treatment with topical corticosteroids and oral antihistamines while identifying and treating the underlying trigger—most commonly herpes simplex virus or Mycoplasma pneumoniae. 1, 2

Initial Assessment and Diagnosis

When evaluating target lesions, confirm the diagnosis by examining for:

• Classic target morphology: Central dark papule or vesicle surrounded by a pale zone with an outer ring of erythema 3
• Distribution pattern: Symmetric involvement predominantly on extremities (especially extensor surfaces) spreading centripetally 2
• Lesion duration: Fixed lesions lasting minimum 7 days (distinguishing from urticaria which resolves within 24 hours) 2
• Mucosal involvement: Check eyes, mouth, nose, and genitalia for erosions or blistering 3

Critical distinction: Differentiate EM from Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), which presents with widespread purpuric macules or flat atypical targets with epidermal detachment, systemic symptoms, and involvement of ≥2 mucosal surfaces 3, 4. This distinction is essential as it dramatically changes management and prognosis.

Identify and Address the Underlying Cause

Immediately obtain:

• Detailed medication history over the past 2 months (including over-the-counter medications) 3
• History of recent infections, particularly HSV or respiratory symptoms 2, 5
• Mycoplasma serology 3

If drug-induced: Discontinue the culprit medication immediately 3, 4. This is the single most important intervention for drug-related cases.

If HSV-associated: Initiate acyclovir treatment 6, 7

If Mycoplasma-associated: Start azithromycin 6

Symptomatic Treatment Protocol

Cutaneous Lesions

First-line topical therapy:

• Apply topical corticosteroids (prednicarbate cream 0.02% or hydrocortisone) to affected areas to reduce inflammation and erythema 1
• Use emollients and moisturizers daily to maintain skin barrier function 1
• Avoid alcohol-containing lotions; use oil-in-water creams or ointments instead 1

For pruritus:

• Oral antihistamines (cetirizine, loratadine, fexofenadine, or clemastine) for grade 2/3 pruritus 1
• Topical polidocanol-containing lotions for additional itch relief 1

Mucosal Involvement

Oral care:

• Maintain oral hygiene with gentle, soap-free cleansers 1
• For severe oral involvement: Mouthwash consisting of aluminum hydroxide/magnesium hydroxide/simethicone (400 mg/400 mg/40 mg) 6

Urogenital involvement:

• Topical 2% lidocaine gel with applicator for urinary discomfort 6
• Consider urinary catheter if significant dysuria or retention occurs 3

Pain management:

• Systemic analgesics as needed (fentanyl was used successfully in severe cases) 6

Severe Cases Requiring Hospitalization

Admit patients with:

• Severe mucosal involvement causing poor oral intake 2, 5
• Fluid and electrolyte imbalance 2
• Inability to maintain adequate hydration and nutrition orally 3

Inpatient management:

• Establish IV access through non-lesional skin when possible 3
• Initiate IV fluid resuscitation with careful fluid balance monitoring 3
• Consider nasogastric feeding if oral intake inadequate 3

Role of Systemic Corticosteroids

Short-term oral systemic steroids are recommended only for grade 3 erythema and desquamation 1. The evidence for systemic corticosteroids in EM is limited and should be reserved for severe cases, as the condition is typically self-limited 2, 7.

Management of Recurrent EM

For patients with HSV-associated recurrent EM:

• Prophylactic antiviral therapy is the treatment of choice 2, 5, 7
• This represents first-line treatment for preventing recurrences 7

For patients not responding to antivirals, consider second-line immunosuppressive agents, though evidence is limited 7.

Important Caveats

Avoid these common pitfalls:

• Do not use topical or oral steroids on vaccination sites containing live virus 3
• Do not apply salves, creams, or ointments (including topical antibacterials) to active vaccination sites 3
• Avoid hot showers or excessive soaps that can worsen skin dryness 1
• Do not trim cuticles or manipulate lesions (increases infection risk) 1
• Avoid greasy occlusive creams that may facilitate folliculitis 1
• Use antibiotics only if secondary bacterial infection is confirmed with bacterial swabs 1

Monitoring and Follow-up

• Lesions typically last <4 weeks and are self-limited 3
• Document progression with photographs showing lesion type and extent 3
• For patients with ocular involvement, arrange ophthalmology follow-up to monitor for long-term sequelae (trichiasis, symblepharon, punctal stenosis) 6