Headache is a common symptom that often interferes with functional activities but is rarely life-threatening. Headache can be a primary disorder (migraine, cluster headache or tension-type headache) or a secondary symptom of a number of disorders including acute systemic or intracranial infections, intracranial tumors, head trauma, severe hypertension, cerebral hypoxia, eye, ear, nose and throat disorders, oral and dental disorders and cervical spondylosis. Sometimes the cause may not be found. Headaches can be caused by irritation, traction or pressure on any pain-sensitive structure in the head, including all the tissues covering the skull, the 5th, 9th and 10th cranial nerves, the upper cervical nerve, the large intracranial venous sinuses, the large cerebral arteries at the base of the skull, the large dural arteries and the dura mater at the base of the skull. Dilation or constriction of the vessel walls can stimulate nerve endings and cause headaches. The cause of most headaches is extracranial rather than intracranial. Strokes, vascular malformations and venous thrombosis are uncommon causes of headache. Diagnosis Knowledge of the frequency, duration, localization, severity, factors that make the headache better or worse, accompanying signs and symptoms (e.g., fever, neck stiffness, nausea and vomiting), and specific ancillary tests can help to define the cause of the headache. Some secondary headaches can exhibit specific features. Acute, severe full-blown headaches with fever, photophobia and cervical tonicity are suggestive of infectious disease, such as meningitis, unless refuted by evidence. Subarachnoid hemorrhage can also cause acute headache with signs and symptoms of meningeal irritation. Occupational lesions often cause subacute, progressively worsening headaches. New onset headaches that present after the age of 40 should always be taken seriously and must be carefully evaluated. Headaches due to intracranial occupational lesions may present as morning headaches on awakening or as painful awakenings during sleep, fluctuating with position changes, and often accompanied by nausea and vomiting. Additional neurological complaints such as convulsive episodes, confusion, limb weakness or sensory disturbances may appear late, suggesting a dangerous condition. Tension-type headaches tend to be chronic or persistent, usually starting in the occipital or bifrontal areas and spreading throughout the head. It is often described by the patient as a feeling of heavy pressure or tightness in the head. Febrile illnesses, arterial hypertension, and migraines often cause throbbing headaches that can occur anywhere on the head. Useful laboratory tests include routine blood work, syphilis serology, biochemistry, sedimentation and cerebrospinal fluid examination; if specific symptoms are present, appropriate tests such as visual examination (visual acuity, visual field, refractive disorders, intraocular pressure), or paranasal sinus radiographs are required. If the cause of a recent, persistent, recurrent, or progressively worsening headache is not clear, CT and/or MRI should be performed, especially if there are abnormal neurological signs. Treatment Many headaches are of short duration and do not require treatment other than light analgesics (e.g., aspirin or paracetamol) and rest. The treatment of primary headache is discussed separately below. There are advocates for the use of alternative therapeutic measures to formal treatment, such as biofeedback, acupuncture, dietary therapy, and certain less conventional treatment modalities to treat these disorders. In rigorous evaluation studies, none of them has proven to have definite efficacy. However, these treatments, which are considered unorthodox, do not pose a significant risk to the patient, so it may be worthwhile to give them a try, considering that there are multiple modalities available for effective headache treatment. The treatment of secondary headaches depends on the treatment of the underlying disease. For meningitis, immediate antibiotic treatment is crucial. Subsequently, analgesics including paracetamol, non-opioid anti-inflammatory drugs or opioid narcotics can be applied to treat the headache symptomatically. Some conditions require more specific treatment; for example, temporal arteritis requires treatment with adrenocorticosteroids, while benign intracranial hypertension must be treated with acetazolamide or diuretics, along with weight loss. Subdural hematomas or brain tumors require surgical treatment. Stress management taught by a psychologist often leads to a reduction in the incidence of headache. But most cases do not require intensive psychotherapy, as long as the physician is sympathetic, acknowledges that the patient’s headache is real, follows the patient regularly and encourages discussion of emotional difficulties, whether they are antecedent or consequential to the chronic headache. The physician can tell the patient that there is no organic pathology, eliminate unnecessary concerns, and make specific suggestions for readjustment to the environment and elimination of stimuli and stressors. For particularly difficult problems, a team of clinicians, psychotherapists and physical therapists is most effective.