Most healthy kids get sick once in a while. No matter how well you take care of yourself, you can't always avoid germs that others are carrying. Some common illnesses and conditions caused by germs are acne, athlete's foot, bronchitis, chicken pox, colds, croup, ear infections, head lice, influenza, step throat, tonsillitis, and warts.

Acne

Pimples and blackheads (usually on the face) are known as acne. Acne is caused by bacteria and oil in the skin that clog the pores, which then become inflamed. There is no way to prevent acne; most young people get some form of it.

Athlete's Foot

You don't have to be an athlete to get athlete's foot. Sneakers worn without socks make the ideal environment for fungus growth. The fungus causes the skin to itch and peel, especially between the toes.

Bronchitis

The trachea, a big tube that carries air from the throat to the chest, forks and becomes two main bronchi, one going to each lung. When bacteria or viruses invade the cell lining of the trachea or bronchial tubes, the infection is called bronchitis.

Chicken Pox

Not too long ago, just about everyone got chicken pox (except chickens). It's caused by a virus that spreads easily when an infected person coughs or sneezes. The chicken pox rash is made up of clear blisters, called vesicles, on the skin. They are very itchy and form scabs when they dry. Until recently, 98 percent of children in the U.S. got chicken pox between the ages of 1 and 10. In 1995, the Food and Drug Administration approved the varicella virus vaccine, which is 70 to 90 percent effective in preventing the virus.

Cold

People get colds more than any other illness, often two or more a year. Colds are caused by viruses in the respiratory tract, not because you played in the cool air too long!

Croup

When a virus attacks the larynx (voice box), the voice becomes hoarse and squeaky. The accompanying cough may sound like a seal's bark, and it may hurt to cough.

Ear Infection (acute otitis media)

Fluid normally escapes from the ear through the Eustachian tube, which leads to the back of the nose and throat. Ear infections occur when the Eustachian tube becomes swollen and does not let the fluid out. This fluid presses on the eardrum and causes pain.

Head Lice

Head lice are tiny insects that breed in people's hair and spread easily from one person to another. They look like dandruff flakes, but they are stuck firmly to the strands of hair. Head lice won't make you sick but do cause a terrible itch, an allergic reaction to the insects.

Influenza (flu)

The flu is caused by a virus that infects the entire respiratory tract. Your head, muscles, and throat hurt, and you may have a high fever. True influenza can be a serious illness, though people often use the term “the flu” to describe minor respiratory infections.

Strep Throat

This is an infection of the back of the throat caused by the streptococcus bacteria, which affect the cells in the lining of the throat. The damaged cells and other nearby cells send out fluid, which causes the throat to swell and become very red and sore. The redness is caused by additional blood coming into the area.

Tonsillitis

A painful sore throat can mean tonsillitis, when the tonsils become enlarged and swollen. Pus sacs develop, and it hurts to swallow.

Warts

Warts are caused by a virus in the skin cells which causes rapid growth of the skin's outer layer. A hard bump forms on the surface of the skin.

Plantar's warts got their name because the wart “plants” itself within the foot and the roots grow inward. Plantar's warts are very painful because of the pressure placed on them from walking.