A. Any headache fulfilling criterion C
B. Separation anxiety disorder has been diagnosed according to DSM-5 criteria
C. Headache occurs exclusively in the context of actual or threatened separation from home or from major attachment figures
D. Not better accounted for by another ICHD-3 diagnosis.
Separation anxiety disorder is persistent, typically lasting at least six months, although a shorter duration may meet diagnostic criteria in cases of acute onset or exacerbation of severe symptoms (eg, school refusal, or complete inability to separate from home or attachment figures). The disorder causes clinically significant distress and/or impairment in social, academic, occupational and/or other important areas of functioning.