Oral Manifestations of Pediatric Multisystem Inflammatory Syndrome

Pediatric multisystem inflammatory syndrome (MIS-C) is a rare condition associated with COVID-19, with few reports on its oral manifestations. A 13-year-old male pediatric patient with presented with fever, diarrhea, odynophagia, conjunctival hyperemia, rash, and bipalpebral edema. On physical examination, he exhibited diffuse ulcerated lesions with crusts on the vermilion border and labial mucosa, primarily affecting the labial commissures. Initially, immune-mediated diseases such as erythema multiforme or Stevens-Johnson syndrome were suspected, and treatment with topical corticosteroids and photobiomodulation was initiated. However, the lesions worsened, and polymerase chain reaction (PCR) testing of a sample from the lesion confirmed herpes simplex virus type 1. Given the diagnosis, corticosteroid therapy was discontinued, and decontamination using antimicrobial photodynamic therapy (methylene blue 0.01%, 5 min, 660 nm, 100 mW, 6 J/point, energy density of 199.98 J/cm2) was performed. However, oral lesions and overall systemic condition worsened, and the patient died. This case highlights the need for a differential diagnosis of oral lesions in MIS-C in order to carry out the most appropriate treatment.