Tension headache

A tension-type headache (TTH) is the most common form of primary headache. It is often called a stress headache. These headaches account for nearly 90% of all headaches reported. The pain usually affects both sides of the head. It often radiates from the neck, the eyes, or the lower back of the head. The sensation is typically described as a pressing or tightening feeling. It is non-pulsating, meaning it does not throb like a heartbeat.

To be classified as a TTH, an attack must follow specific rules. The pain must last between 30 minutes and 7 days. It should be of mild or moderate intensity. The pain must not be made worse by routine activities like walking or climbing stairs. Additionally, there should be no nausea or vomiting. A person might experience sensitivity to bright light or loud sounds, but usually not both. Some people also feel tenderness in their scalp when it is pressed.

The way these headaches work involves complex pathways in the body. Scientists believe they involve both peripheral and central pain pathways. Peripheral pathways receive signals from the pericranial myofascial tissue, which is the protective tissue around the muscles of the head. In episodic TTH, these peripheral signals play a major role. However, if the pain becomes chronic, the body may undergo central sensitization. This is a process where the central nervous system becomes hyperexcitable. This change happens in the trigeminal spinal nucleus, the thalamus, and the cerebral cortex.

Central sensitization changes how the brain processes signals at the synaptic level. This involves neurotransmitters like glutamate, serotonin, and nitric oxide. Nitric oxide (NO) is especially important because it can cause vasodilatation and activate pain pathways. There are two main types of synaptic changes: homosynaptic and heterosynaptic facilitation. Homosynaptic facilitation occurs when the synapses normally used in pain pathways change their receptors. This lowers the person's pain threshold. Heterosynaptic facilitation occurs when synapses not normally used for pain begin to participate. This can cause allodynia, where harmless touches feel painful.

Doctors use the International Classification of Headache Disorders (ICHD-3) to group these headaches. There are two main categories: episodic (ETTH) and chronic (CTTH). ETTH occurs less than 15 days per month or less than 180 days per year. CTTH is more frequent, occurring 15 days or more per month for at least three months. ETTH can be further divided into frequent and infrequent types based on the number of days per month.

The impact of these headaches on the world is quite large. A 2016 Global Burden of Disease study showed that TTH affects about 1.89 billion people. The condition is more common in women, affecting 30.8% compared to 21.4% in men. Most people experience these headaches between the ages of 35 and 39. In 2016, TTH resulted in 7.2 million years of life lived with disability (YLDs). This YLD figure is calculated using the prevalence and the average time spent with the headache.

Managing tension headaches involves several different approaches. For immediate relief of episodic headaches, people often use over-the-counter medications like paracetamol or ibuprofen. For those with kidney or stomach issues, paracetamol is often preferred. However, using these medicines too often can lead to medication overuse headache. For chronic cases, doctors may prescribe tricyclic antidepressants like amitriptyline for prevention. Lifestyle changes can also help. Maintaining good posture, staying hydrated, and using stress management techniques are all helpful ways to reduce the frequency of attacks.