To the Editors: Myocarditis is an inflammatory disease of the myocardium that most often affects young individuals and is the cause of approximately 10% of sudden deaths in young adults. Myocarditis, which occurs as the complication of measles itself, is still very rare as not many studies present this case, especially in children. This vaccine-preventable viral disease became an outbreak with cases rising to 32-fold in 2022 due to the COVID-19 pandemic.1 Here we present a case of measles-associated myocarditis in a 3-year-old unvaccinated girl presented with altered mental status, fever, maculopapular rash, cough, coryza and shortness of breath in the emergency department of Ciawi Public Hospital. Clinical features and 2 positive contact histories diagnosed the suspicion of measles infection. The patient had never been vaccinated. She was isolated in the pediatric intensive care unit, and the treatment was symptomatic. On physical examinations, we observed sunken eyes and right-eye unilateral ptosis. Koplik's spots were missing, but the oral mucosa was erythemic, vulnerable and bled easily. We also found pigeon chest, intercostal and epigastric retractions on inspiration with crackles, wheezing and cardiomegaly with audible systolic murmur at the apex upon auscultation (Figure 1).FIGURE 1.: (Above) Pigeon chest (pectus excavatum) with intercostal retraction and hyperpigmented maculopapular rash (convalescence stage) were seen. (Below) Congenital unilateral ptosis was identified.Laboratory findings included a high increase of N-terminal prohormone of brain natriuretic peptide (9898 pg/mL). Chest radiograph revealed cardiomegaly with pulmonary edema and pneumonia. Electrocardiogram changes suggested inverted T waves in lead V4–V6 and sinus tachycardia. She also had mild mitral and tricuspid regurgitation on echocardiography. Antistreptolysin-O test was negative and thyroid hormone levels were unremarkable. The patient was immediately isolated. The patient was given oxygen supplementation with a non-rebreathing mask at 6 L/min. Symptomatic therapy with intravenous infusions to correct mild-moderate dehydration (Ringer lactate 350 cc/4 hours, following Kaen3B fluid 1100 cc/day), antipyretic therapy (acetaminophen 120 mg q12h), vitamin A supplementation (200,000 IU/day for 2 days), and an antibiotic such as ceftriaxone (600 mg/day) for pneumonia were initiated. Inhalation therapy with salbutamol was also given. The patient achieved complete remission within 10 days. Despite being rare, approximately one-fourth of the patients with measles-associated myocarditis can lead to heart failure or even sudden cardiac death. Patients with mild symptoms usually improve spontaneously. Repeat echocardiography may be necessary to evaluate the clinical improvements. In conclusion, measles is still an important viral infection worldwide. We should consider measles as one of the potential causes of myocarditis as it can lead to fatal complications and death. Early recognition, isolation of patients, and registration by the certified boards help to limit outbreaks.2,3 Symptomatic treatment is sufficient, but complications are common. Improved vaccination programs are necessary to protect citizens.