Tension headache

Tension headache, stress headache, or tension-type headache (TTH), is the most common type of primary headache. The pain usually radiates from the lower back of the head, the neck, the eyes, or other muscle groups in the body typically affecting both sides of the head. Tension-type headaches account for nearly 90% of all headaches.

Pain medications, such as paracetamol and ibuprofen, are effective for the treatment of tension headache. Tricyclic antidepressants appear to be useful for prevention. Evidence is poor for SSRIs, propranolol and muscle relaxants.

The 2016 Global Burden of Disease study revealed that TTHs affect about 1.89 billion people and are more common in women than men (30.8% to 21.4% respectively). TTH was most prevalent between ages 35 and 39. Despite its benign character, tension-type headache, especially in its chronic form, can impart significant disability on patients as well as burden on society at large. In 2016, the global burden of TTH was reported to be 7.2 million years of life lived with disability (YLDs). The YLD was calculated using TTH prevalence and average time spent with TTH multiplied by percentage health loss caused by TTH (3.7%).

According to the third edition of the International Classification of Headache Disorders, the attacks must meet the following criteria:

Tension-type headaches may be accompanied by tenderness of the scalp on manual pressure during an attack.^{[citation needed]}

Various precipitating factors may cause tension-type headaches in susceptible individuals:

Although the musculature of the head and neck and psychological factors such as stress may play a role in the overall pathophysiology of TTH, neither is currently believed to be the sole cause of the development of TTH. The pathologic basis of TTH is most likely derived from a combination of personal factors, environmental factors, and alteration of both peripheral and central pain pathways. Peripheral pain pathways receive pain signals from pericranial (around the head) myofascial tissue (protective tissue of muscles) and alteration of this pathway likely underlies episodic tension-type headache (ETTH). In addition, pericranial muscle tenderness, inflammation, and muscle ischemia have been postulated in headache literature to be causal factors in the peripheral pathophysiology of TTH. However, multiple studies have failed to illustrate evidence for a pathologic role of either ischemia or inflammation within the muscles. Pericranial tenderness is also not likely a peripheral causal factor for TTH, but may instead act to trigger a chronic pain cycle. This is when the peripheral pain response is transformed over time into a centralized pain response. These prolonged alterations in the peripheral pain pathways can lead to increased excitability of the central nervous system pain pathways, resulting in the transition of ETTH into chronic tension-type headache (CTTH). Specifically, the hyperexcitability occurs in central nociceptive neurons (the trigeminal spinal nucleus, thalamus, and cerebral cortex) resulting in central sensitization, which manifests clinically as allodynia and hyperalgesia of CTTH. Additionally, CTTH patients exhibit decreased thermal and pain thresholds which further bolsters support for central sensitization occurring in CTTH.

The alterations in physiology that leads to the overall process of central sensitization, involves changes at the level of neural tracts, neurotransmitters and their receptors, the neural synapse, and the post-synaptic membrane. Evidence also suggests that dysfunction in supraspinal descending inhibitory pain pathways may contribute to the pathogenesis of central sensitization in CTTH.