Abstract
We describe an elderly female patient with known polymyositis who presented with new onset temporal headache that was diagnosed as giant cell arteritis but subsequently had a typical clinical course of cluster headache. This case illustrates the potential for diagnostic confusion between giant cell arteritis (GCA) and cluster headache (CH) and the need to consider CH as a potential differential diagnosis in those newly presenting with headaches, even in the elderly, and relapsing headaches in subjects with a diagnosis of GCA. Importantly, this needs to include female patients, a group historically thought to be much less likely to develop CH.