Giant cell arteritis (temporal arteritis)

Giant cell arteritis is inflammation of medium and large arteries, often those around the head and scalp, in which immune cells including T-cells and macrophages gather in the artery wall and form clusters called granulomas that can narrow the vessel and reduce blood flow.

It mainly affects people over fifty, and a global meta-analysis estimated a pooled incidence of roughly 10 cases per 100,000 people over fifty and a pooled prevalence of roughly 52 per 100,000, with rates highest in Scandinavian countries at around 22 per 100,000. It is more common in women, with studies describing a female-to-male ratio near 1.7 to 1. It often overlaps with polymyalgia rheumatica, which brings shoulder and hip stiffness, and because it can threaten vision, it is treated as a medical emergency with urgent, specialist-led care.

Common signs

A new headache, often at the temples, scalp tenderness, jaw pain or fatigue when chewing, vision changes, fever, and unintended weight loss. It often overlaps with polymyalgia rheumatica, which brings shoulder and hip stiffness. Sudden vision loss is a warning sign that needs immediate care.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.