Occasionally, within a few days after children receive dental treatment, groups or clusters of painful blisters or sores may occur on or around the lips. These sores, often called cold sores or fever blisters, may first appear as reddish areas and can progress to ulcers quickly. The sores can be very painful. The child will usually have a fever, headache, and be irritable. The child will not want to eat or drink because of the significant discomfort on the lips and in the mouth.

These multiple sores are the result of an oral herpes virus (herpes type 1 virus) that has been activated in the mouth of your child. The oral herpes virus can be activated by a number of factors including stress, chemical or physical insult, food or liquid sensitivity, or change in their immune response. The stress of dental treatment can, therefore, activate the virus. The virus is present in about 90 percent of children under age ten. Once it occurs as a primary attack, the child starts to develop immunity towards future attacks. However, it can reoccur as a mild attack around the lips in a significant number of children and adults when the virus is reactivated by such things as trauma, sunburn, stress, dental treatment, etc.

For the initial outbreak and infection, the duration of the illness is usually two weeks. Signs and symptoms of the viral infection typically occur within the first week and improve in the second week. As this is a contagious disease, it is recommended that the child be kept at home with limited exposure to others.

Over-the-counter, aspirin-free pain and fever relief medications should be used according to product label directions. Over-the-counter topical paste such as Orabase-b or Zilactin can be applied to the ulcers around the lips two to four times per day with a cotton swab. Toothpaste and brushing might be very painful, so use disposable gauze or Toothettes to carefully wipe the teeth and mouth.

Children should be encouraged to drink bland liquids such as water, carbonated liquids, etc., as often as possible to keep hydrated. Avoid the use of salty, spicy, acidic, and hot liquids or foods.

All people should avoid contact with the sores. All utensils, cups, plates, etc., used by the child should not be shared and should be washed in extremely hot water with detergent after each use.

For recurring lip sores, the blisters quickly form unsightly scabs and usually heal within one week. Over-the-counter topical anesthetics may help. Definitive control of the blister outbreak is limited to topical antiviral medications that provide temporary relief from discomfort but will not speed up the healing process. Currently there is no cure for recurrence of this viral infection. However, it is thought that antiviral therapy reduces the degree and severity of the outbreaks.