Temporal ultrasonography findings in temporal arteritis: early disappearance of halo sign after only 2 days of steroid treatment

Temporal arteritis (TA) is the most common chronic systemic vasculitis, frequently involving superficial temporal arteries, hence the name. Diagnosis of TA is based on clinical, laboratory and histological findings, as recommended by the ACR criteria. Nevertheless, over the past few years colour Doppler ultrasonography (CDU) of temporal arteries has emerged as a valid non-invasive diagnostic tool. The main specific CDU finding is the halo sign, a dark hypoechoic circumferential wall thickening around the artery lumen predominantly due to an acute inflammatory process of the arterial wall that tends to disappear a mean of about 2 weeks after the start of steroid treatment [1]. We observed the case of a 79-year-old woman with TA in which the halo sign disappeared after only 2 days of steroid treatment (Fig. 1). This case underlines that temporal CDU aspects have to be considered when performing CDU of temporal arteries, making it desirable to perform this examination before starting steroid therapy. Considering that current guidelines are very clear about the importance of starting high-dose steroids immediately on suspicion of TA, CDU must be performed immediately rather than delaying steroids while this examination is being arranged.