A total of 42 children with erythema multiforme (aged 0.1 to 15.8 years, median 6.1 years) were treated between 1978 and 1997 at the Department of Paediatrics, University of Bern, Switzerland. Antecedent infections were noted in 30 cases: Mycoplasma pneumoniae infection (n = 14), acute upper respiratory tract disease (n = 10) and herpes simplex infection (n = 6). Four cases were associated with antecedent medication (n = 3) or immunization (n = 1). In 12 of the 30 patients in whom erythema multiforme followed an infectious disease, drugs described in the literature as inducers of erythema multiforme had been given for symptoms not suggestive of the condition. In the remaining eight children no precipitating agent could be detected.
Conclusion: In this survey infections were found as a definite or at least presumptive trigger of erythema multiforme in 71% of cases. Drugs (including immunization) implicated as triggers of erythema multiforme played a definite causative role in 10% and a presumptive role in a further 29% of patients. In 19% of patients an associated condition was not diagnosed.