Portuguese Man-o'-war (Physalia physalis) Envenomation in a Child: First Confirmed Case in Malaysia

We report the first confirmed case of Physalia physalis (Portuguese man-o'-war) envenomation in Malaysia, involving a 9-y-old boy who sustained a sting while swimming off Labuan Island. He experienced sudden, intense burning pain in his right forearm. Visible tentacles were removed by the father, who also irrigated the area with vinegar before bringing the boy to the emergency department. The child arrived in visible distress, crying, with a linear erythematous papular rash and transiently elevated blood pressure (135/85 mm Hg) and heart rate (120 beats/min), but otherwise the boy remained hemodynamically stable. Intravenous morphine (0.1 mg·kg^-1) provided effective analgesia, and the boy was admitted for observation. A photograph of the marine organism confirmed characteristic features of P physalis. Nematocysts were identified on a skin sample using the cellophane tape method and light microscopy. This case highlights gaps in region-specific guidelines and emphasizes the need for public education on marine envenomation in tropical settings.