Health Library

Achondroplasia is a group of rare genetic (inherited) bone disorders. Achondroplasia is the most common type of what was once called dwarfism, in which the child's arms and legs are short in proportion to body length.

Most people get an occasional bout of heartburn—that burning feeling in the chest about a half-hour after eating. But if you get it often, you may have GERD.

This test is done to find out if you have tuberculosis. Your doctor might order this test if you have a lung infection or symptoms of TB.

Acne affects teens and adults of all ages. It happens when oil secreted by sebaceous glands clogs the hair follicle. Bacteria infect the clogged follicle and cause pimples.

Acne is a disorder of the hair follicles and sebaceous glands. Hair follicles are the areas around the base or root of each hair. Sebaceous glands are the tiny glands that release oil (sebum) into the hair follicles. The sebum moistens the skin and hair. The sebum and hair get to the skin surface through tiny holes called pores.

Learn about acne with this multiple-choice quiz. You'll learn, for example, which factors promote blackheads.

Acoustic neuroma is a rare noncancer tumor. It affects hearing and balance when the tumor presses on the nerves in the inner ear.

If you have hemophagocytic lymphohistiocytosis, your immune system does not work normally. Certain white blood cells - histiocytes and lymphocytes - attack your other blood cells. These abnormal blood cells accumulate in your spleen and liver, causing these organs to enlarge.