Side-locked Unilaterality: Cervicogenic or Another Secondary Headache?

Side-locked unilateral head pain is a key diagnostic criterion of Cervicogenic Headache (CGH). However, while this presentation characterises CGH, it is not confirmatory.

There are medical conditions that manifest with unilateral side-locked headache. One of these conditions is Giant Cell Arteritis (GCA) or Temporal Arteritis.  For those who need to become more familiar with GCA…

Giant Cell Arteritis

GCA typically affects individuals over 50, with a peak incidence between 70 and 80 years. The condition is more common in females: 2-3:1.

Signs and Symptoms

Headache in the temporal region occurs in 90 percent of patients.  Other signs and symptoms may include allodynia (excessive tenderness) on the scalp, pain in the jaw muscles when chewing (jaw claudication), which can be an early and specific sign, visual disturbances, including diplopia, blurred vision, and even sudden, painless vision loss in one eye due to ischemia of the optic nerve.  Some have systemic symptoms – fever, weight loss, fatigue, and night sweats.

A history of polymyalgia rheumatica can be a precursor or coexist with GCA.  Around 50 percent of patients with GCA have symptoms of polymyalgia rheumatica, characterised by aching and morning stiffness in the neck, shoulder, and pelvic girdles.

Patients may report a combination of the above symptoms, with headache and visual disturbances being among the most concerning due to the risk of irreversible blindness.


The exact cause is unknown, but it is thought to involve an abnormal immune response, possibly triggered by an infectious agent in genetically susceptible individuals. Inflammatory cells, including giant cells, infiltrate the arterial wall, leading to damage and remodeling.

Your Patient

In summary, if your patient is a 65-year-old female with a recent (< 3 months) unilateral temporal head pain with or without any of the symptoms mentioned above, GCA is a consideration, and early recognition is of the essence.

Until next time

If you are new to Watson Headache®, welcome to the Watson Headache® Approach, an evidence-informed practice when considering the role of the neck in Cervicogenic and Primary Headache.

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