In-depth

Addison's disease

Addison's disease occurs when your adrenal glands produce insufficient amounts of certain important hormones. Treatment may include taking corticosteroids.

Adult Still's disease

Daily fevers, achy joints and an intermittent, salmon-pink rash may be an indication that you have a rare inflammatory disorder called adult Still's disease.

Autoimmune hepatitis

Autoimmune hepatitis — Early detection, medications can help.

Behcet's disease

Behcet's disease affects several body systems and causes a variety of signs and symptoms. Find out what it is and how it's treated.

Bone spurs

Bone spurs can sometimes interfere with joint function or press on nerves.

Brucellosis

Brucellosis is an infectious disease that spreads from animals to people, mainly via unpasteurized dairy products. Travelers should take special care to avoid infection.

Cancer

Learn about cancer, what it looks like and what causes it.

Celiac disease

Celiac disease is an immune reaction to gluten, a protein found in certain foods. As a result, the body is unable to absorb some important nutrients.

Churg-Strauss syndrome

Churg-Strauss syndrome is a rare disorder marked by blood vessel inflammation that affects organs throughout the body. Asthma is the most common sign.

Complex regional pain syndrome

Complex regional pain syndrome is a chronic, painful disease that typically affects an arm or leg that was recently injured or infected.

Dengue fever

Dengue fever is a sometimes fatal viral disease spread by mosquitoes in tropical and subtropical areas of the world. Learn how to protect yourself.

Diabetic neuropathy

Diabetes can damage nerves throughout your body — a condition known as diabetic neuropathy. Nerve damage can cause pain, disability and other serious complications.

Dislocation

A blow to your joint can dislocate the bones that meet at that joint. Don't try popping them back into place yourself. Get medical help.

Ebola virus and Marburg virus

Ehrlichiosis

Ehrlichiosis is a tick-borne disease that causes flu-like symptoms. When you're outdoors, be aware of steps to prevent tick bites.

Encephalitis

Encephalitis is inflammation of the brain usually caused by a viral infection. Severe cases can cause brain damage, even death.

Gonorrhea

Gonorrhea is a highly contagious sexually transmitted infection. Without treatment, serious complications can occur.

Hemochromatosis

Hemochromatosis causes your body to store large amounts of iron, which can cause life-threatening complications. The simple treatment is to regularly remove blood.

Hepatitis C

Hepatitis C is a highly infectious disease that's usually contracted from contaminated blood.

Histoplasmosis

The fungus that causes the lung disease histoplasmosis lurks in soil, chicken coops and caves. Find out if you're at risk.

HIV/AIDS

More than 39 million people are living with HIV — the virus that causes AIDS. Millions more are likely to become infected in the next decade.

Hypothyroidism

Although low levels of thyroid hormones (hypothyroidism) can leave you feeling tired and depressed, medications can help you live a normal life.

Kawasaki disease

Kawasaki disease — the leading cause of acquired coronary disease in children — causes artery wall inflammation throughout the body. It affects children younger than age 5.

Lupus

Lupus is a chronic disease that can affect your skin, joints and organs. With proper care, most people with lupus live relatively active, healthy lives.

Lyme disease

Lyme disease is a tick-borne illness. Left untreated, it can lead to serious and lingering complications — including arthritis.

Mixed connective tissue disease

Mixed connective tissue disease features signs and symptoms of a combination of disorders — primarily lupus, scleroderma and polymyositis.

Myocarditis

Myocarditis is a disease in which the heart muscle becomes inflamed and swollen, often as the result of an infection.

Parvovirus infection

Parvovirus infection is a common childhood illness with a distinctive cheek rash. In some adults, including some pregnant women, it can be serious.

Pituitary tumors

Pituitary tumors are abnormal growths in the pituitary gland in the brain. Most are noncancerous (benign). Some may cause overproduction of hormones and associated problems.

Polio

One of the most feared diseases of the 20th century, polio has been eradicated from the developed world but remains a threat in less developed nations.

Premenstrual syndrome (PMS)

Premenstrual syndrome (PMS) can make you miserable in the days before your monthly period. Here's how to handle it — bloating, depression and all.

Pseudogout

Signs and symptoms of pseudogout may seem similar to those of gout, but the causes and treatment of the two conditions are completely different.

Pulmonary fibrosis

Pulmonary fibrosis results from scar tissue that forms in your lungs. This affects your ability to breathe and obtain enough oxygen.

Reactive arthritis

Reactive arthritis is an inflammatory condition that develops in response to an infection in another part of your body.

Rheumatic fever

Rheumatic fever, an inflammatory disease triggered by untreated or poorly treated strep throat, can cause permanent heart damage.

Rubella

Rubella, a contagious viral infection, is most dangerous to pregnant women. Rubella can be prevented with the combined measles-mumps-rubella vaccine.

Sacroiliitis

Sacroiliitis is one cause of low back pain and discomfort. It's an inflammation of the sacroiliac joints, which connect the lower spine and pelvis.

Septic arthritis

Septic arthritis occurs when a joint becomes infected. Find out more about this serious condition.

Takayasu's arteritis

Takayasu's arteritis is an uncommon form of vasculitis that affects the large arteries.

Valley fever

Valley fever — This common fungal infection in America's desert regions causes few, if any, problems for most people, but for some it can be life-threatening.

Vasculitis

Vasculitis is an inflammation of the blood vessels. It can affect people of any age. Treatment depends on the type of vasculitis.

Wegener's granulomatosis

Wegener's granulomatosis is an uncommon disease that causes blood vessel inflammation that can damage lungs, kidneys and other organs. Untreated, it can be fatal.

Wilson's disease

Mar. 21, 2013