BEST CHILD DENTAL SPECIALIST! An eruption cyst (or eruption hematoma) is a small, fluid-filled sac that can form on the gums while a tooth erupts. Eruption cysts are most common in young children but can occur in infants or adults. Eruption cysts typically appear as a small, rounded swelling on the gums. They tend to have a translucent bluish color. These cysts may be tender to the touch and cause discomfort or pain. But they are generally benign and don’t cause long-term harm. Tooth eruption (in children). If you have infants or school-aged children, chances are you’re all too familiar with the pain that tooth eruption can bring. In infants, this usually occurs around six months in age. Older children will begin to lose their primary teeth around age six or seven. If you’re dealing with tooth pain, give us a call or visit our website to book an appointment. We at Apple Dental will do our best to get you feeling better quickly.