Diseases & Conditions

These masses of minerals form in your bladder. That's the organ that holds your urine. Both men and women get bladder stones, but they are more common in men over 50.

We all have ear wax. It's natural and healthy. But what is it, exactly? Why do we have it, and what does ear wax do for our ears? Let's take a moment to learn about it.

This immune system reaction is triggered by certain foods. Your immune system can react if you eat, touch or breathe in particles of the food. Even a very small amount can trigger a reaction. Many types of foods cause immune system reactions. Some common examples are shellfish, peanuts, tree nuts, eggs, milk, wheat and soy.

This immune system reaction is triggered by peanuts. With this allergy, your immune system reacts if you eat peanuts or foods that have peanuts in them. Even a very small amount can trigger it. Some people with this allergy react to touching peanuts, or to breathing in dust with peanut particles in it.

This condition is a dangerous overheating of your body. It happens when your core temperature reaches 104 degrees Fahrenheit (40° Celsius). Heat stroke is a medical emergency.

This skin and tissue damage comes from extreme cold. Frostbite can happen to any part of your body. And it can be very serious.

This is a problem with your thyroid. That's a hormone-producing gland in your neck. The thyroid makes hormones that help control many activities in your body. These hormones affect things like your metabolism and heart rate. With hyperthyroidism, your thyroid makes more hormones than your body needs.

This is a problem with your thyroid. That's a hormone-producing gland in your neck. The thyroid makes hormones that help control many activities in your body. These hormones affect things like your metabolism and heart rate. With hypothyroidism, your thyroid does not make enough hormones to meet your body's needs.

This is a growth of cells in your thyroid. The thyroid is a hormone-producing gland in your neck. It makes hormones that help control many activities in your body. A thyroid nodule can interfere with your thyroid's function.

This condition is an abnormally low number of platelet cells in your blood. Platelets are tiny cells that help your blood clot to stop bleeding. If your platelets are destroyed, or if your body can't produce enough new cells to meet your needs, you can develop a shortage. You can be at risk for excessive bleeding, including internal bleeding. This is a medical emergency.

Radon is a gas that comes up through the ground. You can't see it or smell it. But when you're exposed to it, especially for many years, it can be harmful. It's a leading cause of lung cancer.

This is a dangerous buildup of serotonin in your body. That's a chemical your body makes naturally. It's used by your brain and your nervous system. It helps regulate things like body temperature, digestion and breathing. But too much serotonin can be bad for you.

This is a life-threatening condition. It's an immune response that's so intense it causes inflammation throughout your body. It can lead to organ failure.

This is a label given to a group of disorders. In these disorders, nerves or blood vessels are compressed in the space between your collarbone and the underlying rib. This space is called the "thoracic outlet."

This is an open sore that usually forms on your leg above your ankle. Venous ulcers can be painful, and they can become infected. They are often slow to heal.

Your nose gets stuffy when blood vessels in the inner lining of your nose become inflamed. You may have a runny nose, too, which makes breathing even harder. For most people, a stuffy nose isn't a serious problem. But it can be a nuisance.

A vascular malformation is an abnormal growth of blood or lymph vessels. It doesn't shrink over time. It continues to grow slowly during life.

If you have too much serotonin in your body, it can lead to dangerous side effects. This is known as serotonin syndrome.

This dangerous disease is caused by a virus. It can infect all mammals. The virus spreads through saliva, and attacks the brain and spinal cord. By the time symptoms appear, it's almost always fatal.

This is excessive sweating. With this condition, you sweat a lot even when you aren't active or overheated. You may find that you're constantly trying to control your sweating. This can disrupt your daily life.

Serum sickness is an immune system reaction. It is triggered by antiserums or antivenins, and by certain types of proteins in medicines used to treat an infection or condition.

SSLR is linked to certain medicines used to treat an infection, and to other health conditions.

A food allergy is when your body has a bad immune reaction to a certain food. This is different than a food intolerance, which does not affect the immune system. Read on to learn more.

Peritonitis is a redness and swelling (inflammation) of the tissue that lines your belly or abdomen. This tissue is called the peritoneum.

A phobia is a fear of something. Generally, agoraphobia is a fear of situations that are hard to escape.

This sheet explains the procedure and your recovery.

Ehlers-Danlos syndrome (EDS) is a group of rare genetic disorders. These disorders affect the way collagen is made or used in the body.

Hemochromatosis is a condition in which a person's body is overloaded with iron. The extra iron builds up in various organs and can cause health problems. This video discusses the possible causes of hemochromatosis, typical symptoms, and what treatments are available.

This condition is a problem with your blood. If you have anemia, you don't have enough healthy red blood cells. These are the cells that carry oxygen through your bloodstream. Without enough red blood cells, your body's cells don't receive enough oxygen.

These are disorders that are caused by a problem with our genetic code, which we call "DNA." You can be born with a genetic disorder. Or, you can develop one later in life. Let's take a few minutes to learn more.

This is a disorder of the immune system. It affects the thyroid. That's a hormone-producing gland in your neck. Your thyroid makes hormones that help control many activities in your body. Graves' disease causes your thyroid to make more thyroid hormone than your body needs. We call that "hyperthyroidism."

This is a disorder of the immune system. It affects the thyroid. That's a hormone-producing gland in your neck. The thyroid makes hormones that help control many activities in your body. Hashimoto's disease damages your thyroid and keeps it from making enough thyroid hormone for your body's needs. We call that "hypothyroidism."

This is a disorder of the blood. With it, your blood doesn't clot the way it should. If you get cut or have an internal injury, you can bleed for a long time. That's very dangerous.

This viral infection affects the liver. It's a short-term infection that doesn't cause lasting harm. A vaccine has made hepatitis A infections rare in the United States.

This viral infection affects the liver. It causes the liver to swell, and damages liver cells. You can have a short-term hepatitis B infection that gets better without causing lasting harm. Or, you can have a chronic infection. This may cause permanent liver damage.

This viral infection affects the liver. The virus that causes hepatitis D only infects you if you also have hepatitis B. If you get both infections at the same time, you may get better with no lasting harm. But when you have a chronic hepatitis B infection and then get hepatitis D, this is serious. It may lead to permanent liver damage.

If you or someone you love has been diagnosed with sickle cell disease, you may be facing some unexpected challenges. Here are some things you can do to manage sickle cell disease.

Lyme disease is an illness spread by the bite of an infected tick. A bull's-eye rash is a typical symptom that identifies this illness, which untreated can affect many parts of the body. This video explains how the illness develops and what you can do to protect yourself against tick bites.

This chronic autoimmune disease results in the immune system attacking the body's own healthy cells. Lupus most commonly affects women age 15-44. It causes tissue damage and inflammation, and can affect any part of the body.

If you're diagnosed with lupus, you may face some unexpected challenges. But lupus doesn't have to take over your life. These tips will help you manage it.

This is a bacterial infection you get from a tick bite. It can spread through your body, causing flu-like symptoms. In some people, it can cause problems that last a long time.

Watch this video to learn about the unique problems sickle cell disease can cause in women.

This is an inherited blood disorder in which the red blood cells are abnormally shaped. Sickle cell anemia can prevent tissues in the body from receiving enough oxygen. It can cause a wide range of complications.

Vasculitis is inflammation of the arteries and veins. It can damage organs and tissues.

In the digestive system, cystic fibrosis (CF) mainly affects the pancreas. A child with CF has trouble absorbing fats, as well as some proteins and vitamins.

This disease is a disorder of the blood. With it, the shape of red blood cells becomes distorted. They can clump together and get stuck within small blood vessels. Sickle cell disease can cause problems throughout the body.

This genetic disease causes copper to gradually build up inside your body. Over time, the copper gets to toxic levels. It harms your tissues and organs.

Detailed information on cystic fibrosis and its effect on the reproductive system.

Detailed information on cystic fibrosis and its effect on the respiratory system.

Children with cystic fibrosis often have poor weight gain. This can happen even when they get enough calories. Read on for details on how to make sure your child gets enough nutrients--and what to do if your child isn't gaining weight.

Detailed information on the genetics involved in cystic fibrosis.