Mumps is a contagious viral infection that used to be common in children before the introduction of the MMR vaccine.
It's most recognisable by the painful swellings at the side of the face under the ears (the parotid glands), giving a person with mumps a distinctive "hamster face" appearance. Other symptoms of mumps include headaches, joint pain and a high temperature, which may develop a few days before the swelling of the parotid glands.