Is Erythema Multiforme Rare in Children?
Erythema multiforme is indeed rare in children, though not as rare as Stevens-Johnson syndrome/toxic epidermal necrolysis, and becomes increasingly uncommon in younger age groups, particularly infants.
Epidemiology and Age Distribution
Pediatric EM is considered an uncommon condition 1. The systematic review of 580 pediatric cases found a mean age of 5.6 years (range 0.1-17 years), with only 19 infants (3.2%) reported 1. This age distribution demonstrates that EM becomes progressively rarer in younger children, with neonatal cases being extremely rare—only three cases described in the literature as of 2011 2.
Key Points on Rarity:
- Infants are significantly less prone to develop EM major compared to older children (P < 0.01) 1
- The condition is "extremely rare in infancy" 2 and "said to be rare in childhood and especially in early infancy" 3
- When EM does occur in infants, it tends to be EM minor (17 of 19 cases) rather than EM major 1
Clinical Context and Differential Diagnosis
The perception of rarity must be understood in context. EM is frequently overdiagnosed in children, particularly when clinicians mistake urticaria multiforme for EM 4, 5. The British Association of Dermatologists guidelines emphasize that "previous publications and reports of SJS/TEN in children and young people may have been biased by misclassification of diseases" 6, suggesting historical confusion between EM and more severe conditions.
Common Pitfalls:
- Urticaria multiforme has "waxing and waning" lesions versus EM's fixed lesions 5
- EM should not be confused with Stevens-Johnson syndrome, which has much more substantial mucous membrane involvement and widespread erythematous or purpuric macules with blisters 5
- EM major does not progress to SJS/TEN—patients are typically constitutionally well and make good recovery 6
Triggers in Pediatric Population
When EM does occur in children, infectious agents are the predominant triggers:
- Herpes simplex virus: 17.9% of cases 1
- Mycoplasma pneumoniae: 15.7% of cases 1
- Drug-related: 24.1% of cases 1
- Vaccines are a particular trigger in infants (9 of 19 infant cases, representing 47% of infantile EM) 1
Recurrence Patterns
Recurrent EM affects 14.3% of pediatric cases and tends to occur in older children rather than infants 1. When recurrence happens, HSV is the trigger in 61% of cases 1. This is clinically relevant because recurrent erosive oral ulcerative lesions in children should prompt consideration of EM, especially when resembling primary herpetic gingivostomatitis 7.
Prognosis
Long-term sequelae are rare (1.3%) 1, and the prognosis is usually good 4. This favorable outcome distinguishes pediatric EM from the more severe SJS/TEN spectrum, where mortality and long-term complications are significant concerns 6.