1Pediatric Unit, Foundation IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, via della Commenda 9, IT-20122 Milan, and Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy, 2Pediatric Department of Southern Switzerland, Bellinzona, and Università della Svizzera Italiana, Lugano, and 3Department of Pediatrics, University Children’s Hospital of Bern, Inselspital, Bern, Switzerland. E-mail: email@example.com
We read with interest the report by Siedner-Weintraub et al. (1), who found that only 30 out of 119 children with an initial diagnosis of erythema multiforme (EM) (20 girls, 10 boys, age range 4–18 years) met the Bastuji-Garin classification criteria recommended for diagnosis of this condition. Of the initially misdiagnosed cases, 59 had a non-specific eruption, 29 had features consistent with urticaria multiforme and 2 had acute haemorrhagic oedema of young children. Stimulated by this report, we re-evaluated the characteristics of 35 Swiss children with an initial diagnosis of EM (2–4). The diagnosis of EM was confirmed in only 18 cases (12 girls, 6 boys, age range 4–13 years). Of the 17 initially misdiagnosed cases, urticaria multiforme was diagnosed in 8 cases (3 girls, 5 boys, age range 4 months to 12 years), acute haemorrhagic oedema of young children in 6 cases (2 girls, 4 boys, age range 2–19 months), and non-specific eruption in the remaining 3 cases (2 boys, 1 girl, age range 3 months to 13 years).
In conclusion, EM exclusively affects children ≥ 4 years of age. Furthermore, acute haemorrhagic oedema of young children is often misdiagnosed either as EM or as non-specific eruption. Diagnosis of acute haemorrhagic oedema is made clinically in children ≤ 24 months of age, who do not appear ill, who present: (i) with targetoid lesions predominantly over the cheeks, ears and extremities (with relative sparing of the trunk), (ii) often tender non-pitting oedema of the face, auricles, and extremities, and (iii) without pruritus.
1Pediatric Clinic, Kupat Cholim Meuhedet, and 2Department of Dermatology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. E-mail: firstname.lastname@example.org
Our study re-examined cases of paediatric erythema multiforme (EM) in our tertiary medical centre, in order to better characterize this condition in children (1). Of 119 children given a diagnosis of EM, only 30 met clinical criteria and were included in the study. Mean age was 11.3 years and no cases were identified in children younger than 4 years of age. Common misdiagnoses were urticaria multiforme, non-specific eruptions, and acute haemorrhagic oedema of infancy. Unlike in adults, herpes simplex virus was not a common pathogen, while the most common infectious agent identified was Mycoplasma pneumoniae, suggesting that cases associated with this infection may represent the recent entity, mycoplasma-induced rash and mucositis (1).
These findings are further confirmed by Milani et al.’s correspondence. On re-evaluating their own cases of paediatric EM, Milani et al. were able to ascertain the diagnosis of EM in only 18 out of 35 children. Children with EM were older than 4 years of age and misdiagnoses similar to those observed in our study were identified.
Based on both studies, it appears that EM does not exist in infants and toddlers. We suggest that when targetoid lesions are observed in this age group, other diagnoses should be considered, mainly urticaria multiforme and acute haemorrhagic oedema of infancy.