Getting to the bottom of childhood stomach pain can be a Herculean task. A sampling of possible causes include constipation, food allergy, stress or anxiety, indigestion, stomach flu, irritable bowel syndrome, wanting to watch TV instead of go to school, lactose intolerance, acid reflux and, it turns out, a condition known as "abdominal migraine."
If you've never heard of abdominal migraine, you're not alone. Its existence is oddly absent from the general knowledge base, though it's not that rare. Studies show a prevalence of up to 4 percent in children and adolescents (for comparison, the Centers for Disease Control and Prevention puts childhood food allergy at 4 percent to 6 percent), and one study found it to account for up to 15 percent of childhood cases of recurrent abdominal pain.
At its most basic, abdominal migraine is a stomach ache that lasts anywhere from an hour to a few days, and it's painful enough to interfere with daily life. The pain is typically in the navel area and often accompanied by vomiting, nausea and cramping.
It's a childhood phenomenon: Almost all youth who suffer them have a family history of migraine headaches and grow up to have those instead. Teri Roberts, co-founder and chair of the American Headache and Migraine Association, writes on Health Central the condition is most common in 5- to 9-year-olds. Others put the average onset around age 7 and the peak incidence around age 10.
It's not a migraine, strictly speaking — migraine is a headache disorder. Abdominal migraine is considered a variant, one of several "childhood episodic syndromes" that appear to be precursors to migraine.
"It is probably better to look at migraine as syndrome rather than a type of headache, and migraine syndrome in childhood may have several different presentations at different age groups," says Dr. Ishaq Abu-Arafeh, consultant pediatrician at Forth Valley Royal Hospital in Lambert, Scotland, via email.
Abu-Arafeh, who specializes in childhood headache, says possible presentations include infantile colic, episodes of "head tilt" (paroxysmal torticollis), attacks of dizziness (benign paroxysmal vertigo), cyclical vomiting syndrome and finally abdominal migraine.
"One of my patients had torticollis as a baby, cyclical vomiting as a toddler, abdominal migraine in early childhood and typical migraine without aura in late childhood," he reports.
Aside from the recurrent stomach pain, abdominal migraine looks a lot like migraine headache, just minus the headache. According to Abu-Arafeh, both include "sensory symptoms such as intolerance to light, noise or smell, gastroenterological symptoms such as loss of appetite, nausea and vomiting and vasomotor changes such as pallor, sweating and change in temperature (feeling hot or cold)."
Exactly what causes all of this isn't well-understood. Dr. Peter Goadsby, director of the Headache Center at the University of California San Francisco, explains it as a signaling error whereby certain stimuli, or "triggers," lead to a faulty perception of pain.
"Migraine is a disorder of sensory integration that results in the brain receiving an excess 'message.' Take light sensitivity [in migraine headache] for example ... no extra light gets to the eyes -- the brain mis-interprets the light arriving as unpleasant. Similarly for abdominal migraine, it is likely a mis-interpretation of information coming from the GI tract," Goadsby writes in an email.
Possible triggers for abdominal migraine are similar to those for migraine headache and include psychological stress, physical exhaustion, motion sickness, chocolate and foods containing monosodium glutamate (MSG) or nitrites.
Because abdominal migraine is still somewhat mysterious, physicians currently treat it like they do migraine headache — with drugs like NSAIDS (aspirin or ibuprofen), serotonin blockers, tricyclic antidepressants and valproic acid. For adolescents and the occasional adult with abdominal migraine, doctors may prescribe a class of drug called triptans, but they're not approved for younger children by the U.S. Food and Drug Administration.
That's assuming medical experts successfully identify abdominal migraine. It's a diagnosis of exclusion, and with so many other possible causes of abdominal pain, it can take a while to get there, if at all. Many experts think the condition is underdiagnosed, mistaken for conditions like stomach flu, constipation, irritable bowel syndrome and food intolerance.
It's especially tough to spot "in children with infrequent episodes (around one to two per year) or in children with short attacks lasting only few hours," notes Abu-Arafeh.
To further complicate matters, young children may have trouble describing their symptoms. Dr. Andrew Hershey, for one, thinks some children diagnosed with abdominal migraine may in fact be suffering plain-old migraine headaches with the usual accompanying nausea and vomiting.
Hershey, director of neurology and the Headache Center at Cincinnati Children's Hospital, thinks doctors may be asking the wrong questions.
"In young children," he writes in an email, "the child and family may focus their symptom observation on their stomach complaints without addressing the head pain — no one asks the child or they can't vocalize the symptoms, hence abdominal migraine."
Hershey doesn't like the term. He notes, "There may be a small subgroup of patients that have the recurrent abdominal pain as isolated symptoms from the migraine, but this should not be called abdominal migraine."
"The biggest mistake," Hershey says, "is not asking the child if their head hurts."