Mouth blisters and cold sores usually are small, clear and fluid-filled, crop up on mucus membranes, and are caused by the herpes simplex virus.

These sores occur anywhere around the mouth, sometimes in a small cluster, and usually disappear within 1-2 weeks, even without treatment. The most common ones start out with a tingling on the edge of the lip, and within 24 hours you develop a full-blown sore.

Another type of mouth blisters is canker sores, which occur only inside the mouth and are not contagious. They sometimes occur as a result of trauma, but may also crop up without any known reason.

Canker sores are painful, open ulcers, and are white and yellow, surrounded by a bright red area. Unlike canker sores, cold sores are very contagious, and often come back in the same location.

Canker and cold sores cannot be prevented or cured. OTC medications help to relieve the pain. Some products can be used inside the mouth while others are only for use outside the mouth.

Your pharmacist can help you choose the best product to use if you have either canker or cold sores. You should see your doctor or dentist if the sore gets worse or does not heal in two weeks.

Hand, foot and mouth disease is common in babies and children under age 10, but it can also affect adults. The US Centers for Disease Control and Prevention say it’s not at all related to foot-and-mouth-disease that occurs in farm animals.

Symptoms usually include fever, rash on the palms of the hands and the soles of the feet, and mouth blisters. Since a virus causes HFMD, there is no treatment.

If your baby’s temperature spikes, and he feels irritable and loses his appetite, he may have hand, foot and mouth disease, also known as Coxsackie virus.

Children spread HFMD before symptoms appear (like most viruses) so it’s tough to avoid. The primary means of transmission is contact with saliva and feces. The fever may end in a few days, but the blisters last longer.

Although no treatment is available for this condition, you can treat the symptoms to provide relief from the fever, aches, and pain of these blisters.

Preventive measures include frequent hand washing, especially after diaper changes, disinfection of contaminated surfaces by household cleaners, and washing soiled articles of clothing.

Children are usually excluded from childcare programs, schools and other group settings during the first few days of the illness.