Erythema Multiforme

Question 1

What is Erythema Multiforme (EM)?

Answer 1

A distinct cutaneous condition previously thought to be part of the SJS/TEN spectrum, but now considered a separate entity.

Question 2

What is the most common aetiology of EM?

Answer 2

Infection, usually recurrent herpes simplex virus (HSV) or Mycoplasma pneumoniae.

Question 3

How does the aetiology of EM differ from SJS/TEN?

Answer 3

EM is most commonly triggered by infections, whereas SJS/TEN is most commonly triggered by drugs.

Question 4

In which population is EM more common?

Answer 4

Children

Question 5

What is the classic lesion seen in EM?

Answer 5

The target lesion, consisting of three concentric rings: a central erythematous or purple plaque (may blister), a pale ring, and a red halo.

Question 6

Where does EM typically occur?

Answer 6

It can occur at any site, but involvement of the palms and soles is characteristic.

Question 7

How does mucosal involvement in EM compare to SJS/TEN?

Answer 7

Mucosal involvement in EM is usually milder than in SJS/TEN.

Question 8

What is the usual duration of an EM episode?

Answer 8

7–14 days.

Question 9

Can EM recur?

Answer 9

Yes, it may recur, especially if triggered by infections like HSV.

Question 10

What is the general approach to treating EM?

Answer 10

Symptomatic management:

• Encourage oral fluids
• Frequent gargling with glycothymol or saline
• Use non-adherent dressings on eroded skin
• Prevent adhesions if mucosal lesions present
• Treat underlying cause (e.g., antiviral therapy for HSV)