What is mumps? Mumps is a respiratory infectious disease that occurs mostly in children and adolescents, most commonly in winter and spring. It is caused by the mumps virus. It is an acute, systemic infection. It is mainly characterized by swelling and pain of the parotid glands. In sick children, the parotid glands on both sides will be swollen on one side, centered on the earlobe, and they will feel warm to the touch. Sometimes you feel pain. If your baby has headache, muscle aches, fever, loss of appetite, vomiting, throat swelling, swelling and pain under the earlobe, he may have mumps. This swelling will reach its peak in about 5 days and will gradually disappear in about 10 days. The average cycle is 18 days. However, during this period, if the baby develops enlarged swelling or unbearable pain, he or she needs to seek medical attention promptly.