context: Maybe you've been feeling short of breath lately. At first it might happen when you exercise, but after a while you have trouble breathing even while you're at rest. Or you may get a hacking cough that's hard to get under control. What's going on, you wonder. There are a lot of possible causes, but your doctor may tell you that you've got a condition called idiopathic pulmonary fibrosis ( IPF). Your symptoms are brought on by scarring in your lungs that makes it hard to breathe. There's no cure, and the disease gets worse over time. But there are things you can do and medicines to take that will make you feel better and live longer. Make sure you don't face things alone. Get the emotional backing you need from your family and friends. Or look for a support group in your area, where you can meet people who know what you're going through. The word "idiopathic" means unexplained. Doctors use it when they can't pinpoint the cause of a condition. That's the case with IPF. Researchers believe some things you may have breathed in could be linked to IPF. For example, if you spend time working around metal or wood dust, or asbestos, you may be at higher risk for the disease. Whatever the cause, IPF leads to scarring in your lungs, which makes your airways thick and stiff. It becomes harder and harder to breathe. About 48,000 people get it each year in the U. S. It can happen at any age, but most people learn they have it when they're between 50 and 75. More men get IPF than women, and men tend to get diagnosed at a later, more serious stage of the disease. IPF can run in families. Some people with the disease have one or more relatives who have it. In these cases, it's known as familial IPF. Cigarette smoking is linked to IPF. So are some infections, such as the flu, Epstein- Barr virus (which causes mononucleosis), hepatitis, and herpes. These things may increase your risk of the disease, although they are not direct causes. People with IPF may also have gastroesophageal reflux disease ( GERD), also known as acid reflux. Scientists don't know if one disease causes the other, but they suspect that people with GERD may breathe tiny drops of stomach acid into their lungs, which can cause damage over time. Your lungs each contain about 300 million tiny air sacs that fill up with oxygen every time you breathe. In healthy lungs, the walls of these air sacs are very thin, so that oxygen and carbon dioxide can easily pass through them. When you have IPF, scar tissue forms on the air sac walls and in the spaces around them, making them thick and hard. Doctors believe that the scarring is caused by something in the body that attacks the lungs over and over, but they don't know what or why. This scarring makes it harder for air to pass in and out of the sacs. That's why you feel out of breath. If you have IPF, you may have rapid, shallow breathing or a dry, hacking cough that doesn't go away. When a doctor listens to your breathing through a stethoscope, he may hear a crackling noise in your lungs. You may also get "clubbing" -- a widening and rounding of your fingertips and toes. You may feel unusually tired or achy, or gradually lose weight without trying. Everyone's situation is different. For some people, the disease gets worse quickly. For others, the symptoms stay more or less the same for years. Doctors haven't figured out a way to get rid of the scarring in the lungs. Over time, you might get complications like a collapsed lung, infections, blood clots, or pneumonia. In some people, IPF can lead to lung cancer. Nowadays doctors are able to diagnose IPF more quickly than before. And once that happens, they can recommend medications, other treatments, or lifestyle changes that can help you feel better and stay as healthy as possible.