Diarrhea is a common symptom of many different problems. It often appears with other symptoms, which may help physicians determine their underlying cause. For example, patients with diarrhea due to infection may also experience abdominal pain, abdominal cramping, fever and blood in the stool, especially when the diarrhea is caused by infection. Nausea and vomiting may also occur with gastrointestinal infections.

Specific combinations of symptoms and their likely causes include:

• Chronic diarrhea. This may be a symptom of lactose or sorbitol intolerance, infection or irritable bowel syndrome (IBS). Additional symptoms of abdominal bloating and excessive gas after consuming dairy products may indicate lactose intolerance. When diarrhea is accompanied by alternating episodes of constipation, as well as abdominal pain and frequent bowel movements, it may indicate IBS. However, patients with these symptoms should seek professional medical advice and not assume these symptoms are due to IBS.
  
  
• Chronic bloody diarrhea. This may be a symptom of inflammatory bowel disease (IBD), especially if accompanied by abdominal pain, cramping and unintentional weight loss.
  
  
• Chronic oily or fatty diarrhea (stool often appears bulky, greasy or foul smelling). This may indicate absorption problems or other digestive problems. It may also indicate pancreatitis, bile duct or liver diseases, celiac disease or complications of intestinal surgery.

In some cases, patients may pass more than a quart of stool each day. Passing large volumes of diarrhea can lead to dehydration, as the body loses significant amounts of water and salt. Dehydration can be life-threatening for the very young, the elderly and people with weakened immune systems.

Signs and symptoms of dehydration in adults include:

• Thirst
• Dry mouth and/or skin
• Fatigue
• Decreased and/or dark-colored urine
• Feeling faint or dizzy
• Low blood pressure
• Eyes that appear sunken

Adults with diarrhea should contact their physician when they become dehydrated or when they experience any of the following:

• Diarrhea for three or more days
• Severe pain in the abdomen or rectum
• Temperature of 102 degrees Fahrenheit (34 degrees Celsius) or higher
• Blood in stool or black, tar-like stool

Infants and children are especially vulnerable to dehydration. Infants can become dehydrated after just one or two days of severe diarrhea. Signs of dehydration in children include:

• Dry mouth or tongue
• Lack of tears when crying
• No wet diapers for three or more hours
• Sunken abdomen, eyes or cheeks
• High fever
• Restlessness, irritability
• Skin that does not flatten after being pinched and released