Although sore throats in older children and adults are commonly a sign of strep throat, most sore throats in infants are caused by viruses, and therefore don't require treatment with antibiotics.
Hand, Foot, and Mouth Disease
This is a common viral infection that is often overlooked because most parents aren't able to get a good look in their infant's mouth when she is sick. A child with hand, foot, and mouth disease (HFMD) usually has a fever, irritability, and ulcers in the back of the mouth. This infection is easier to recognize if the child also has the typical blisters on the palms of the hands and soles of the feet.
Unfortunately, there is no treatment for this common illness. The symptoms can last for seven to ten days, during which time your child will be contagious to others. Symptomatic treatments with pain and fever reducers and making sure your child drinks enough so that she doesn't get dehydrated can be helpful until she recovers. Appropriate pain and fever reducers might include ibuprofen if your infant is over six months old, or acetaminophen. Remember to not give your child aspirin because of the risk of Reye syndrome.
This is another viral infection (this one is caused by the herpes virus) that can cause blisters in a child's mouth. Unlike HFMD, this infection typically causes ulcers on the tongue, gums, and lips and not on the hands and feet.
In addition to a fever, the painful ulcers can make your child irritable and cause decreased appetite. Antibiotics don't help this infection, and the main treatments are aimed at helping to control your child's symptoms.
Tonsillitis and Strep Throat
Parents often confuse the term “tonsillitis” with strep throat. It can help to remember that tonsillitis is a generic term for an infection or inflammation of the tonsils, but it doesn't refer to whether the problem is caused by a virus or bacteria. So even if your child has enlarged tonsils that are red and covered with pus, it doesn't necessarily mean that she has strep. Tonsillitis also can be caused by a viral infection, which, unlike strep throat, doesn't require treatment with antibiotics. Younger children are much less likely to get strep than are older children, but you might have your child tested if she has direct contact with someone who does have strep.