No doubt you’ve heard it more than once: “My tummy hurts!” Probably the most common complaint kids make, recurrent stomach pains occur in up to 15 percent of school-aged children, according to the Children’s Digestive Health and Nutrition Foundation. “Kids are just more susceptible to stomach issues,” says Randy Neustaedter, OMD, author of Child Health Guide: Holistic Pediatrics for Parents (North Atlantic, 2005). “Their digestive tracts are more sensitive, their immune systems aren’t fully developed, they tend to eat a lot of foods that are irritating, and they don’t yet know how to cope with stress, all of which can cause stomach upset.”

Know that signs that mean you should call the doctor

It’s often tricky to determine the cause of a painful stomach. Is it the flu, or slow-movingbowels? Gluten intolerance, or tomorrow’s spelling test? Paying attention to telltale symptoms and asking a few targeted questions can help you figure out what’s causing your kid’s tummy woes.

Possible culprit: food poisoning

Fever, diarrhea, vomiting, and cramps are the most common signs of gastroenteritis, a nonspecific catchall term for a gastrointestinal infection. Viral gastroenteritis (commonly called stomach flu) is usually self-limiting, lasting only a few days. Food poisoning, a type of gastroenteritis, manifests with similar symptoms but is potentially more serious because it can cause severe diarrhea, which may lead to life-threatening dehydration.

Rule out food poisoning by playing detective: Did your child eat something unusual during the last 24 hours? Did the symptoms come on suddenly and abruptly? If the answer to either question is yes, treatment is usually the same as for common viral gastroenteritis—bed rest, replacing lost fluids—but if symptoms are acute, it’s time for medical attention (see Stomach Pain: When to Call the Doctor.”)

Possible culprit: food allergy or intolerance

At least 4 percent of U.S. children have food allergies, and it’s believed that many more suffer from food intolerances, possibly linked to unhealthful substances in processed foods, says Joel Fuhrman, MD, author of Disease-Proof Your Child (St. Martin’s Griffin, 2006). Inadequate nutrition can predispose a child to develop inflammation or allergies, which can cause respiratory congestion and, more seriously, intestinal damage, which throws off beneficial intestinal bacteria (causing gas or cramps) and may lead to nutrient malabsorption. If your child’s stomach issues manifest two to four hours after eating, or if she’s plagued by gas, chronic congestion, and sinus problems, suspect a food allergy; sensitivities elicit more nonspecific symptoms and can manifest hours after eating the offending food.

If ongoing symptoms seem to have no other cause, try a food-elimination diet: Cut out gluten, dairy, eggs, and other common allergens, such as nuts, soy, and shellfish, and see if symptoms abate in a week or two; then add back one food at a time, keeping a food diary to help pinpoint the trigger(s). You can also ask your doctor for IgG and IgE blood tests, which identify antibodies that appear after exposure to an allergen. Also consider getting an antibody panel for celiac disease, designed to identify antibodies different than those in the food-allergy tests. Once you’ve found the offending food, eliminate it for at least six months, and give your child 30 billion CFUs of a probiotic daily to help heal the intestinal lining, suggests Neustaedter.

Possible culprit: appendicitis

Caused by inflammation of the appendix—a small portion of the large intestine—appendicitis isn’t common; only 80,000 cases, comprising 0.1 percent of all U.S. kids, occur every year. But appendicitis is serious. Because it can mimic gastroenteritis, you’ll need to do some sleuthing. Ask your child to point to where it hurts; appendicitis pain usually starts in the belly-button area then slowly migrates down to the lower right side of the abdomen. The telltale sign: abdominal pain when pressed. “You don’t have to press hard,” Fuhrman says. “[If it’s appendicitis,] even light tapping on the abdomen will cause pain.” An even more specific sign is when pressing doesn’t cause pain but sudden release of the fingers does—a symptom known as “rebound tenderness.” Kids with appendicitis also often lose their appetites one or two days before acute pain, so ask them to identify the first meal they didn’t want to eat. If you suspect appendicitis, get immediate medical attention.

Possible culprit: constipation

If your child complains of cramping, has hard stools or infrequent bowel movements, or strains when going to the bathroom, suspect constipation. Ask questions: “‘Do you have to poop now? When did you last poop?’ can give you an idea of bowel regularity,” Neustaedter says. Eliminate wheat and dairy, which tend to be constipating, and focus on high-fiber foods like apples, beans, and raw vegetables. Prunes and dried fruit are rich in sorbitol, which increases bowel movements, and adequate water intake keeps stools from becoming hard and dry. Some practitioners recommend cod-liver oil to lubricate stools and help bowels along. Don’t give children laxatives, even “natural” ones like senna and cascara; they’re too harsh for kids’ intestines.

Possible culprit: anxiety and stress

“The mind and the gut are intimately related,” Neustaedter says, “and worries have a profound effect on digestive function in kids.” If dietary changes don’t help your child’s unexplained stomach problems, it could be stress. Stomach upset before a performance or exams are obvious; chronic, low-grade worries—like concerns about social standing, excessive homework, or recurring problems at home—are harder to identify.

“Kids don’t have the ability to self-monitor feelings,” Neustaedter says, “so parents need to ask questions like ‘How do you like your teacher? Do you feel like you have a lot of work? How are things with your best friend?’” Then make the time to work with your child on stress solutions. Guided imagery is a powerful tool; teach them to imagine being in a place that’s peaceful, safe, and calm—on a beach, in the mountains, being read to by a loving grandparent. Game-playing, drawing, and daydreaming help kids process fears. For older kids with loaded schedules, a weekly planner or organization system can help them feel in control and less overwhelmed by their responsibilities. And cut back on activities; a day playing hooky with mom or dad may be just what the doctor ordered.