By Bonnie Jacob, Pure Matters

Some people rush to the doctor's office every time they feel a little ill. Others try to tough it out and hope the problem will go away. In either case, there are some symptoms no one should ignore.

Many health problems do take care of themselves over time, says the American Academy of Family Physicians (AAFP). But some symptoms may indicate the possibility of a serious condition and should be evaluated immediately by a health care provider.

To determine if something could be serious, look for changes in the way your body looks, feels or reacts, the AAFP says. If you usually get over a cold in a few days, for instance, it's worth calling your doctor if you have a cough that lingers for a week or two, or if you have other symptoms or chronic medical conditions.

These common symptoms require immediate medical attention.

Chest pain

Such pain could be a symptom of indigestion, a heart attack or another condition. Because chest pain could be serious, it should be evaluated promptly, the AAFP says.

Chest pain from a heart attack varies. Sometimes it feels like a crushing sensation, as though someone is sitting on your chest. Other times it feels like a squeezing or pressure on your chest. Sometimes it's accompanied by nausea or lightheadedness.

If you notice any of these symptoms, call 911 and then chew an aspirin if you are not allergic to it to help prevent further damage. Make sure that the emergency responders are aware that you have taken an aspirin.

Coughing up blood

Blood in sputum could indicate simple bronchitis or irritation of the trachea, but it could also be the result of pneumonia or lung cancer.

If you are young and don't smoke, this symptom is most likely an infection, the AAFP says, but it still should not be ignored. Report this symptom to your doctor immediately. If you smoke or are an older adult, your health care provider will look closely for other causes.

Blood in the urine

Although it may indicate a simple bladder infection, this symptom could also mean something more serious, such as a kidney stone or even a malignancy.

To find out what's going on, your doctor may order a series of tests, including urinalysis and blood tests, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Urinalysis examines the urine for red blood cells, as well as white blood cells, which are a sign of a urinary tract infection, and casts, which are clumps of cells that are a sign of kidney disease. Other tests such as X-rays, ultrasounds or even cystoscopic exams may be necessary. A cystoscopic exam involves looking inside the bladder with a very small tube.

Rectal bleeding

Blood in the stool could be from hemorrhoids, or it could be caused by an active ulcer or colon cancer.

Bright-red blood indicates active bleeding. If there's a lot of blood, it could be life threatening. Call 911 immediately.

If the amount of blood is small, you can usually be evaluated in the doctor's office, but call your doctor right away for advice. Simple tests can detect the presence of blood in the stool and estimate how much you're losing. If tests confirm bleeding, an endoscopy, colonoscopy or sigmoidoscopy will let the doctor see what's going on.

Unusual sores, lumps or lesions