Week 8 - Erythema Multiforme

Question 1

What is erythema multiforme (EM)?

Answer 1

An acute, sometimes recurrent, condition of the skin and mucous membranes with diverse lesions (macules, papules, vesicles, bullae); can progress to Stevens-Johnson syndrome or toxic epidermal necrolysis.

Question 2

What are the most common causes of erythema multiforme?

Answer 2

• Infections: HSV-1 & HSV-2 (most common), Mycoplasma pneumoniae
• Drugs: sulfonamides, penicillin, salicylates
• Others: heavy metals, herbal agents, topical therapies, poison ivy
• Immunosuppression increases risk

Question 3

Which infectious agent is most frequently associated with erythema multiforme?

Answer 3

Herpes simplex virus (HSV-1 and HSV-2). Both Type 1 and Type 2.

Question 4

What type of hypersensitivity reaction is involved in erythema multiforme?

Answer 4

Type IV (cell-mediated) hypersensitivity reaction.

Question 5

What is the characteristic skin lesion in erythema multiforme?

Answer 5

Target (bull’s-eye) lesion – rounded, regular, well-defined, may include macules, papules, vesicles, or bullae; symmetrical on palms, hands, feet, extensor limbs; painful mucosal lesions are common.

Question 6

What is the general management of erythema multiforme?

Answer 6

• Supportive care: oral rinses, topical anesthetics for pain, hydration

Treat underlying cause:
- Azithromycin for Mycoplasma pneumoniae
- Antivirals for HSV
- Systemic corticosteroids may be used for inflammation