Clinical common causes of acute laryngitis in 4-year-old babies are infection, excessive use of voice, gas stimulation, etc. 1. Infection: fatigue, cold, etc. can lead to low immunity, bacteria and other pathogenic microorganisms invade the organism, inducing a local inflammatory response, which can lead to the onset of acute laryngitis. 2. Excessive use of voice: 4-year-old babies speak loudly for a long time or shout loudly, may also damage the mucous membrane of the throat, leading to the onset of acute laryngitis. 3. gas stimulation: 4-year-old baby inhaled into the chlorine, ammonia and other harmful gases or too much production dust, may also cause irritation to the mucous membrane of the throat, resulting in acute laryngitis. There are other clinical causes of acute laryngitis in 4-year-old babies. Parents should take their children to the ear, nose and throat department of the hospital as soon as possible, and cooperate with the doctor to improve the relevant examination to clarify the cause of the disease.