Erythema Multiforme in a Child with Mycoplasma-Associated Infection

An ill-appearing child with several-day history of a “wet-sounding” cough was admitted to our hospital for significantly reduced oral intake. Exam revealed near-confluent, hemorrhagic, exudative, leather-like plaques on his lips (Figure 1). Pinkish red targetoid lesions were scattered over the trunk and extremities (Figure 2, A and B ). Several bullous and superficially eroded lesions were noted on his penis and scrotum (Figure 2, C). There was no Nikolsky sign, significant lymphadenopathy, strawberry tongue, “sandpaper” rash, perineal erythema, or acral desquamation.Figure 2Classic pinkish-red, round, targetoid papules, and plaques present on the extremities (A and B); several more bullous and eroded lesions were present on the penis and scrotum (C).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The overall presentation was consistent with erythema multiforme (EM), with Mycoplasma pneumoniae as the suspected causal agent. Chest x-ray demonstrated a viral or reactive airway disease process without focal consolidation. Labs revealed leukocytosis with markedly elevated C-reactive protein. Diagnosis was confirmed by elevated Mycoplasma IgM titer (5513 U/L; normal <0.76 U/L) and positive mycoplasma PCR for Mycoplasma, obtained directly from a swab of his lips. Following treatment, the patient's appetite and oral intake quickly improved, and he was discharged home. EM is characterized by acute onset of sharply demarcated red or pink macules and papules, progressing to raised targetoid lesions with concentric color change consisting of 3 distinct zones of color: a dusky edematous central area surrounded by a darker, erythematous inflammatory zone further surrounded by a lighter edematous ring, enclosed by an erythematous zone.1Newkirk R.E. Fomin D.A. Braden M.M. EM vs SJS/TEN: subtle difference in presentation, major difference in management.Mil Med. 2020; 185: 1847-1850Crossref PubMed Scopus (9) Google Scholar Histology reflects what is seen clinically, demonstrating a vacuolar interface dermatitis with varying degrees of keratinocyte necrosis.2Elston D.M. Ferringer T. Ko C.J. Dermatopathology.3rd ed. Elsevier, Printed in China2019Google Scholar Mucosal lesions may be present. Absence of the Nikolsky sign helps to differentiate EM from more serious conditions, including Stevens-Johnson syndrome. EM is considered a cutaneous hypersensitivity reaction associated with a variety of antigenic stimuli. Underlying infections are main precipitants.1Newkirk R.E. Fomin D.A. Braden M.M. EM vs SJS/TEN: subtle difference in presentation, major difference in management.Mil Med. 2020; 185: 1847-1850Crossref PubMed Scopus (9) Google Scholar Mycoplasma pneumoniae is a frequent cause within the pediatric population, while herpes simplex remains the most common trigger in adults.3Siedner-Weintraub Y. Gross I. David A. Reid S. Moho-Pessach V. Pediatric erythema multiforme: epidemiological, clinical and laboratory characteristics.Acta Derm Venereol. 2017; 97: 489-492Crossref PubMed Scopus (33) Google Scholar Recurrent or persistent EM may occur with an average of 6 episodes per year for up to 6 to 10 years.4Bolognia Schaffer J.V. Cerroni L. Dermatology.4th ed. Elsevier, Printed in China2018Google Scholar Postinflammatory hyperpigmentation, ocular damage, and organ damage caused by internal EM lesions are rare sequelae. Fortunately, most cases resolve within 2 weeks,1Newkirk R.E. Fomin D.A. Braden M.M. EM vs SJS/TEN: subtle difference in presentation, major difference in management.Mil Med. 2020; 185: 1847-1850Crossref PubMed Scopus (9) Google Scholar,4Bolognia Schaffer J.V. Cerroni L. Dermatology.4th ed. Elsevier, Printed in China2018Google Scholar and patients tend to make a full recovery without long-term complications, as was the case of this child. Ethics approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the patient for publication of this case report and any accompanying images.