Swimmer’s ear is an infection of the outer ear canal that may run from the eardrum to the outside of the head. It's often caused by water left in the ear after swimming or showering. This warm, moist environment of the ear canal helps bacteria or fungi grow. If your ear is red (inflamed) on the outside, swollen, discharging and painful when you touch it, it might be an outer ear infection. Your GP should be able to help you with treatment and will advise to keep the ear dry.