Lower back pain and diarrhea are both very common symptoms. Approximately 80 percent of adults experience low back pain at some point, and diarrhea is one of those symptoms that can just creep up on anyone from time to time.

One study from 2014 of chiropractic patients found that the number of people with low back pain and bowel issues was high, even though there didn’t seem to be a specific cause or link between the two.

If you experience recurring lower back pain and diarrhea, it’s possible that you may have an underlying medical condition. We’ll explain some of those causes below.

Lower back pain and diarrhea that’s accompanied by fever, severe abdominal pain, or a loss of bladder or bowel control may indicate a serious medical condition, such as appendicitis or cauda equina syndrome. Call 911 or go to your nearest emergency department.

Your lower back pain and diarrhea may be completely unrelated, but if your symptoms are recurring, chances are that there’s an underlying medical cause.

Here are some possible causes for these symptoms:

Appendicitis

Appendicitis is the inflammation of the appendix, which is a small organ that extends from the first part of the colon in your lower right abdomen.

The pain from appendicitis usually begins near the navel and spreads to the lower right side of your abdomen. Some people have an appendix that extends behind the colon, which may cause lower back pain.

Other symptoms include:

  • diarrhea or constipation
  • fever
  • loss of appetite
  • abdominal pain that can become severe
  • nausea and vomiting
  • an inability to pass gas

Appendicitis needs immediate treatment. Left untreated, your condition can worsen dramatically in just a matter of hours, and your appendix can rupture.

A ruptured appendix can spread infection through your abdominal cavity and is life-threatening. See a doctor right away if you have symptoms of appendicitis.

Kidney infection

Also called infectious pyelonephritis, a kidney infection is a type of urinary tract infection (UTI) that often begins in the bladder or urethra and spreads upward to one or both kidneys.

A kidney infection can cause permanent damage to your kidneys or spread to your bloodstream when left untreated.

You should see a doctor right away if you experience sudden lower back pain and diarrhea, along with nausea and fever.

Pain in your side or pelvis is also possible, along with symptoms of a lower UTI with cystitis (urinary bladder inflammation). These other symptoms include:

A kidney infection requires immediate treatment with antibiotics to reduce the risk of serious complications. It may require hospitalization.

Fecal impaction

Fecal impaction is when a large, hard dry stool stays stuck in the rectum. It’s most often caused by chronic constipation, which can be associated with the long-term use of certain laxatives.

When you’re constipated, your stool becomes dry and hard, making it difficult to pass. The risk increases if you stop taking laxatives after using them for a long time because your intestines forget how to move stool on their own.

Fecal impaction is more common in older people but can happen to people of any age who experience chronic constipation.

Fecal impaction can cause abdominal and lower back pain and pressure. You may also experience leakage of liquid from your rectum or sudden watery diarrhea after long-term constipation.

Other symptoms can include:

  • cramping
  • bloating
  • rectal bleeding
  • bladder pressure
  • bladder incontinence

Irritable bowel syndrome (IBS)

IBS is a common chronic disorder that’s estimated to affect 10 to 15 percent of the world population.

It’s characterized by a collection of symptoms, such as:

  • bloating
  • abdominal pain
  • diarrhea
  • constipation

While IBS doesn’t lead to cancer or other serious diseases, and isn’t known to permanently damage the colon (the way inflammatory bowel diseases may), it can be very uncomfortable.

The symptoms of IBS can vary and can come and go. Along with abdominal pain, IBS can cause lower back pain and diarrhea, accompanied by nausea.

It can also cause constipation or a combination of diarrhea and constipation that may alternate with each other. Other common symptoms include:

  • cramping
  • excess gas
  • mucus in the stool

Enteropathic arthritis

Enteropathic arthritis is a chronic, inflammatory arthritis that’s associated with inflammatory bowel disease (IBD).

Types of IBD include ulcerative colitis and Crohn’s disease, and roughly 1 in 5 people with either type will develop enteropathic arthritis.

Different types of arthritic diseases can cause similar symptoms or be associated with developing IBD, such as ankylosing spondylitis and psoriatic arthritis.

IBD usually causes diarrhea and abdominal pain. IBD that’s associated with arthritis of the spine can cause lower back pain and diarrhea.

Other symptoms vary depending on the type of IBD and arthritis, and may include:

  • joint pain and stiffness
  • bloody diarrhea
  • cramping
  • loss of appetite
  • fatigue

Pancreatic cancer

Pancreatic cancer accounts for 3 percent of all cancers in the United States, according to the American Cancer Society.

The symptoms of pancreatic cancer vary depending on the type and location of the tumor, and the stage of the cancer. Early pancreatic cancers often don’t cause any signs or symptoms.

The following are possible signs and symptoms:

  • upper abdominal pain
  • back pain
  • nausea
  • dark urine
  • jaundice
  • weight loss
  • poor appetite
  • diarrhea
  • nausea and vomiting

It’s important to remember that many of these symptoms are more often caused by other less serious conditions. If you’re concerned about pancreatic cancer, see a doctor.

There are several medical and at-home treatments for lower back pain and diarrhea, depending on the cause.

General back pain and diarrhea that are unrelated can often be relieved using home remedies. If a medical condition is causing your symptoms, your doctor will need to treat the underlying cause of your lower back pain and diarrhea.

At-home treatments

For lower back pain or diarrhea:

Medical treatments

Medical treatment will depend on the underlying cause of your symptoms. They may include:

  • antibiotics
  • prescription antidiarrheal medication
  • muscle relaxers
  • IV fluids and electrolyte replacement
  • biofeedback
  • anticancer drugs
  • surgery

See a doctor if your symptoms don’t improve after a few days.

Seek emergency care if you experience:

  • severe abdominal or back pain
  • high fever
  • blood in your stools
  • sudden loss of bowel or bladder control
  • severe dizziness or confusion

Occasional lower back pain and diarrhea are fairly common symptoms that may be completely unrelated. Having them together may not indicate an underlying condition.

Any recurring or severe symptoms should be discussed with your doctor so they can rule out more serious causes.