Hesperian Health Guides

Fever Blisters

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HealthWiki > Where There Is No Dentist > Chapter 7 Part 1: Problems You Will See Most Often > Fever Blisters

Herpes virus is a kind of germ that causes fever blisters. Fever blisters are sores that can form inside the mouth on the gums or outside on the lips. Blisters on the inside cheeks only are not from herpes.

Sores inside the mouth are a serious problem that usually affect children between 1 and 5 years old. A child with fever blisters in his mouth can become very sick. He will not be able to eat properly. If he does not drink enough fluids, he can become dehydrated (lose his body water). This is dangerous! Fever blisters are also a problem for people living with HIV.

blisters on the gums.
Inside the mouth
  • Sore throat.
  • Fever.
  • Crying, stops sucking 2 to 3 days before sores appear.
  • Spit spills from the mouth because it hurts to swallow.
  • Painful swelling under the jaw.
  • Bright red blisters on the gums, but not between the teeth. Blisters also may be on the roof of the mouth.Inside the mouth

Medicine cannot kill the herpes virus. The sores will go away by themselves in about 10 days. The treatment is to help the person feel more comfortable and to be sure he gets enough to eat and drink.

  1. Give aspirin or acetaminophen for fever.
  2. Wipe milk or yogurt over the sores to protect them before eating. Wash your hands before touching the inside of someone’s mouth! Then give food that is soft and not spicy. If the person cannot eat, prepare a special milk-oil drink.
  3. Give lots of fluids to drink.
a sore near the corner of the mouth.
On the lips

Sores on the lips usually occur after the age of 5. They often appear when the person is weak and sick (for example, with diarrhea or pneumonia). Usually there is no fever. The blisters soon break open and release water. When they dry, a crust forms. The blisters often return. When sores leak water they can pass infection. If you or anyone else touches them, wash your hands immediately.

To prevent the blisters from becoming infected, put an antibacterial cream or petroleum jelly (Vaseline) on them. If you hold ice against the sores for several minutes each day, it may help them heal faster. See information about more treatment options.

This page was updated:19 Feb 2018