Q: Why won't my hernia go away?

A: Hernias are caused by a combination of muscle weakness and strain. No medicine can make them go away.

A hernia can occur when part of an organ or tissue pushes through an opening or weak spot in a muscle wall, protruding into a space where it does not belong.

The most common symptom is a bulge or lump in the affected area. Hernias don't heal themselves, and tend to get larger and harder to repair over time. Not all hernias need immediate surgery, especially when there is no pain or impact on daily activities.

More than a million people each year undergo surgery for some kind of hernia. There are two main approaches to fixing them: an open repair that requires a large incision, and a minimally invasive laparoscopic technique, which uses a camera to guide instruments via a tiny incision.

Repair may be advised when a hernia is painful or symptoms interfere with daily activities.

It may also be done when the hernia interferes with blood flow or causes a blocked intestine.

Several factors can contribute to hernia reoccurrence. Smoking is one of the biggest risk factors, due to its slowing effect on tissue healing and increased coughing from irritated lungs. Other risk factors include obesity, which puts pressure on the inside, and steroids, which affect the ability to heal. Heavy lifting can also aggravate a hernia.

You can't always prevent the muscle weakness that allows hernias to develop. But you can reduce the strain on your body. To avoid a hernia or keep one from worsening, avoid heavy lifting, persistent coughing, and difficulty with bowel movements or urination, which can cause the abdominal wall to weaken or separate.

Leon E. Clarke is director of surgery and leads the Mercy Hernia Care program at Mercy Philadelphia Hospital.