Chronic daily headache in children and adolescents.

Chronic daily headache (CDH) may be primary or secondary. Secondary causes can be suspected through "red flags" in the history and examination. With a prevalence of at least 1% and several associations, primary CDH is a common, often complex, chronic pain syndrome in children and adolescents. The intricate associations between stressors, psychiatric disorders (especially anxiety and depression), and CDH can be explained by "the limbically augmented pain syndrome" proposed by Rome and Rome. Disorders of sleep and other pain syndromes also may co-occur. For these reasons, a multiaxial classification is ideal. Many with primary CDH have features of both chronic migraine and chronic tension-type headache, contributing to confusion in subtyping. Primary CDH is often transformed from a primary episodic headache type, stressors being most responsible. Genetic factors also may facilitate chronification. Management should be biopsychosocial, family-centered, and often multidisciplinary, drugs being only one component. Treatment is still based on consensus, not evidence. Girls, migraineurs, and those with psychiatric comorbidity, medication overuse, and CDH onset before the age of 13 years and lasting for 2 years or longer, are at high risk for persistence; hence, such patients should be followed up into adult life. A classification for CDH should be included in the third edition of the International Classification of Headache Disorders.