Headaches are common in children, increasing in incidence from early childhood to adolescence. They account for 0.7% to 1.3% of all pediatric emergency department visits.   Headaches may be classified as primary or secondary.  Primary headaches include migraine, tension-type, and cluster headaches. Secondary headaches are symptomatic of an underlying intracranial or medical condition that requires treatment. The initial evaluation of acute headache aims to determine whether there is a secondary cause for headache that requires urgent intervention.
Headache may be classified in terms of time course.
A single episode of headache pain without prior headaches.
May represent the first or an unusually severe form of primary headache.
May suggest a new acute secondary cause for headache that, therefore, requires evaluation.
Acute recurrent headache
Stereotyped headaches separated by headache-free periods.
Most suggestive of a primary headache disorder, especially if the pattern has persisted for a long period.
May also occur in secondary headache, as with intermittent elevation in intracranial pressure.
Chronic progressive headache
A gradual increase in headache.
Suggestive of an expanding intracranial lesion.
Of children with brain tumors, 62% have headache prior to diagnosis, and 98% have at least one neurologic symptom or abnormality on examination. 
The most common symptoms include nausea or vomiting, difficulty walking, visual symptoms, focal weakness, or personality change. 
The most common signs include papilledema, abnormal eye movements, ataxia, abnormal reflexes, and visual field or acuity defects. 
Chronic nonprogressive headache
Constant steady headache.
May be due to a chronic type of primary headache or similar secondary etiologies.
A: At least 5 attacks fulfilling criteria B-D
B: Headache attacks lasting 1 to 72 hours
C: Headache having at least 2 of the following characteristics:
Unilateral location, may be bilateral, frontotemporal (not occipital)
Moderate or severe pain intensity
Aggravation by or causing avoidance of routine physical activity (e.g., walking, climbing stairs)
D: During the headache, at least 1 of the following:
Nausea or vomiting
Photophobia and phonophobia, which may be inferred from behavior
E: Not attributable to another disorder.
Diagnosis of migraine with aura requires:
A: At least 2 attacks fulfilling the criteria B-D
B: Aura consisting of at least 1 of the following, but no motor weakness:
Fully reversible visual symptoms (flickering lights, spots, or lines)
Fully reversible sensory symptoms, including positive features (pins and needles) or negative features (numbness)
Fully reversible dysphasic speech disturbances
C: At least 2 of the following:
Homonymous visual symptoms or unilateral sensory symptoms
At least 1 aura symptom developing gradually over >5 minutes or different aura symptoms occurring in succession over >5 minutes
Each symptom lasting >5 minutes and <60 minutes
D: Not attributable to another disorder.