Why Do Cluster Headaches Occur On Just One Side of the Head?

Cluster headaches are a very unique type of headache for many reasons. For example, they are most common among men, they can be triggered by seasonal changes, and they are marked by several hours of severe pain on one side of the head. In contrast, many other types of headaches create more generalized pain that exists on various parts of the head. Cluster headaches are also considered to be among the most painful headaches that exist. This is a discussion of why cluster headaches are experienced on a certain side of the head, whether they can change sides, and if the pain can radiate to other parts of the body.

Why One Side of the Head Is Primarily Affected

Medical professionals believe that the hypothalamus, which is small part in the center of the brain, plays a role in causing cluster headaches. This is the part of the brain that controls automatic functions, such as body temperature, digestion regulation, and many other important functions. Although the exact cause of cluster headaches is still unknown, one widely accepted theory is that the hypothalamus can malfunction and cause the carotid arteries to enlarge and press on certain nerves. There is a bundle of trigeminal nerves on each side of the head, and it is possible that just one of those bundles is affected at a time. The pain that is created on one side of the head is typically centered behind the eye or outwards a bit further towards the ear. On that same side, an individual who is suffering from a cluster headache will also likely experience a red eye, increased tear flow, a reduced pupil size, and a drooping eyelid in that one eye.

The Phenomenon of Switching Sides

Something interesting about cluster headaches is that they do have the ability to switch from one side of the head to the other. Some individuals experience cluster headaches on the same side of the head every time they occur. However, it is possible for this type of headache to switch to the other side in subsequent episodes. Also, it is possible for a person to experience chronic cluster headaches for a while and then switch to episodic cluster headaches at a later time. A designation of “episodic” means that the headaches occur cycles lasting one week to one year and are separated by pain-free periods of at least a month.

How Pain Radiates Through the Body

Although one side of the head is predominantly affected during a cluster headache, it is also possible for the pain to radiate into other parts of the body as well. The most common body parts that a cluster headache will spread to are the nose, teeth, neck, and shoulders on the same side as the head pain. This type of bodily pain is typically described as a burning or piercing sensation.

Recognizing and Treating Cluster Headache Pain

The symptoms of cluster headaches are unique and can typically be diagnosed easily by an experienced physician. Other treatment options to discuss with a doctor for severe symptoms include triptan medications, capsaicin topical creams, and preventative measures to control blood pressure and nerve inflammation.