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.

Back pain

Back pain is a common reason for health care visits and missed work. Home treatment and proper body mechanics can help you feel better.

Bird flu (avian influenza)

A type of influenza normally found in birds, bird flu first appeared in humans in 1997. Experts worry it could lead to a flu pandemic.

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.

Chronic fatigue syndrome

Chronic fatigue syndrome is a complex disorder characterized by extreme, prolonged fatigue. Although its cause is unknown, its symptoms may be relieved.

Cold sore

Cold sores are common and annoying. You can't cure or prevent them, but you can take steps to lessen their frequency and duration.

Cyclospora infection

Cyclospora infection is an uncommon foodborne intestinal infection that causes diarrhea. Outbreaks have been linked to contaminated water and produce.

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.

Dermatomyositis

Dermatomyositis is an inflammatory muscle disease that causes muscle weakness as well as a skin rash. Treatment improves both problems.

Ebola virus and Marburg virus

Ebola virus and Marburg viruses cause hemorrhagic fevers, serious and potentially life-threatening illnesses.

Ehlers-Danlos syndrome

Ehlers-Danlos syndrome (EDS) includes a group of uncommon genetic disorders that mainly affect the joints, skin and walls of blood vessels.

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.

Endocarditis

Endocarditis is an infection of the heart's inner lining. Find out who's at risk.

Generalized anxiety disorder

Don't be a captive of your worries and fears. Control your anxiety by seeking treatment and learning coping skills.

Genital herpes

Genital herpes is a highly contagious sexually transmitted infection. The sores associated with the disease go through cycles of outbreaks and healing.

Hangovers

Hangovers are the unwelcome result of drinking too much alcohol. However unpleasant, most hangovers go away on their own within eight to 24 hours.

Hantavirus pulmonary syndrome

Hantavirus pulmonary syndrome is initiated by a rodent-carried virus that infects the lung tissues, bringing on flu-like symptoms, respiratory problems and even death.

Hemophilia

Hemophilia occurs when your body lacks one of several clot-forming proteins called clotting factors. The result is prolonged bleeding, which can be life-threatening.

Hepatitis A

Hepatitis A virus causes a highly contagious liver infection. Find out how to recognize it and when treatment is required.

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 lipkely to become infected in the next decade. 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.

Hypercalcemia

Hypercalcemia is a higher than normal calcium level in your blood. The most common causes are an overactive parathyroid gland and certain cancers.

Hypoparathyroidism

Hypoparathyroidism is a disorder in which your parathyroid glands secrete abnormally low levels of parathyroid hormone, causing symptoms such as muscle aches.

Hypothyroidism

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

Influenza (flu)

Don't let the flu set you back. Find out how to protect yourself from getting sick with the flu.

Jet lag disorder

Flying across multiple time zones disrupts your natural body rhythms, leading to sleep problems and other symptoms. Learn how to put jet lag to rest.

Legionnaires' disease

Legionnaires' disease, a severe form of pneumonia, is caused by bacteria that can live in water in air conditioning systems, showers and spas.

Listeria infection

Most people exposed to listeria don't become ill. But for those at risk of a listeria infection — a foodborne illness — the consequences can be severe.

Mixed connective tissue disease

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

Muscle cramp: How to provide relief

Muscle cramps come on suddenly, and they're often painful. But self-care measures usually help.

Myofascial pain syndrome

Myofascial pain syndrome is caused by sensitive knots of tissue in your muscles.

Peripheral artery disease

Peripheral artery disease is a common circulation problem affecting the arteries carrying blood to your limbs. Painful in itself, it could signal larger circulatory problems.

Plague

Plague is a disease carried by rats and other rodents. The risk of developing plague is low, and most cases occur in Africa.

Pneumonia

There are at least 50 kinds of pneumonia — a serious lung infection that takes the lives of more than 60,000 Americans every year.

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.

Polymyositis

Polymyositis is an inflammatory muscle disease that causes muscle weakness. Treatment can improve your muscle strength and function.

Porphyria

Porphyria is a group of inherited disorders that cause buildup of natural chemicals (porphyrins), which can result in nervous system and skin problems.

Post-polio syndrome

Some people who've had polio may experience effects of the illness decades later, including new muscle weakness and fatigue, as a condition called post-polio syndrome.

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.

Pulmonary fibrosis

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

Salmonella infection

Salmonella infection will cause only diarrhea and stomach pain in some people, but for infants and immunocompromised people, this bacterial illness can cause life-threatening complications.

Severe acute respiratory syndrome (SARS)

Severe acute respiratory syndrome (SARS) has sickened people worldwide. Although effective treatments aren't yet available, common-sense precautions may help you avoid infection.

Staph infections

The bacteria that cause staph infections are everywhere, including on your skin and in your nose. Learn how to protect yourself from these potentially dangerous germs.

Syphilis

Syphilis, a sexually transmitted infection, first appears as painless sores on your genitals, rectum or mouth. Early diagnosis is important.

Takayasu's arteritis

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

Toxic shock syndrome

Toxic shock syndrome is a life-threatening infection often associated with the use of superabsorbent tampons. But it can also occur in men and children.

Trichinosis

Trichinosis is a roundworm infection you get from eating undercooked, infected pork or other meats. Medications can eliminate the parasite and treat symptoms.

Vasculitis

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

Viral hemorrhagic fevers

Ebola and Marburg viruses and yellow fever belong to a group of potentially deadly illnesses called viral hemorrhagic fevers. Find out about risk.

Yellow fever

A vaccine can protect you against yellow fever — a sometimes deadly mosquito-borne disease found in sub-Saharan Africa and South America.

Apr. 09, 2013