[Headache in the emergency department].

Headache is one of the most frequent symptoms leading to visits at the emergency department. Here, we aim at presenting a pragmatic algorithm for headache patients at the emergency department. The basic principle is taking a detailed history of the current headache with a focus on dynamics, phenotype and trigger factors as well as a possible preexisting headache. "Red flags" should be interrogated specifically. Hypotheses of the etiology of the headache should be generated in combination with the clinical examination (vital signs, neurological exam, otorhinolaryngological and ophthalmological exams) and should be tested appropriately with imaging, laboratory, cerebral spinal fluid studies and ultrasound. Secondary headache have to be treated with a causal approach, if necessary also symptomatically. When a secondary headache can be excluded, we recommend aiming for a primary headache diagnosis with subsequent specific therapy. When a headache patient can be discharged, we recommend scheduling a follow-up appointment to understand the development of a secondary headache and its cause. In case of a primary headache, optimizing prophylaxis and acute therapy is important to prevent future emergency department visits.