Objective: To study the clinical features of patients with headache and agreement between clinical diagnoses and ICHD II criteria diagnosis in primary headaches in Thai children.
Material and Method: Patients with headache who, over a 4-year period, consulted the neurological clinic, were interviewed by questionnaire, examined, diagnosed, treated, and followed up by pediatric neurologists. The result from the questionnaire was used to define the type of headache according to the ICHD II criteria. The clinical features were analyzed and clinical diagnosis was compared with diagnoses using the International Classification of Headache disorders.
Results: Three hundred and seventy-five primary headache patients were defined by ICHD II criteria. One hundred twenty eight (35.2%) were migraine, 47 (12.5%) were tension-type, 123(33.3%) were probable migraine, 31(8.3%) were probable tension-type, and 40(10.7%) cannot be classified because the symptoms were not compatible with diagnosed criteria. Using clinical diagnosis as the standard, the sensitivity of the ICHD -based definition of migraine without aura and probable migraine was 89.96% whereas the specific was 65.09%. On the other hand, the sensitivity of the International Classification of Headache disorders-based definition of infrequent episodic tension-type and probable infrequent episodic tension-type was 56.34% whereas the specific was 87.50%.
Conclusion: The present study shows the increase of sensitivity but decrease of the specificity of ICHD II criteria in diagnosed pediatric migraine headache. However, the duration of attack and quality of headache are still the limitation of diagnosis for pediatric headache. Therefore, the diagnosis criteria in pediatric headache should be developed distinctly from adults.

Keywords: Primary headache, Migraine, International Classification of Headache Disorders Criteria