To the Editor:

Drs. Liozon and colleagues have interestingly evaluated the frequency of a low erythrocyte sedimentation rate (ESR) at diagnosis in a large series of giant cell arteritis (GCA) patients. Their data support the results of our population-based study. The occurrence of GCA with a low ESR is not a rare event. Therefore, when other clinical findings suggest a diagnosis of GCA, a low ESR should not constitute a reason to delay glucocorticoid therapy.

Furthermore, Drs. Liozon and colleagues demonstrated that C-reactive protein (CRP) was more sensitive than the ESR in identifying active disease in GCA at diagnosis. CRP values were elevated in 6 of 12 patients with normal ESR. Similarly, we observed that the CRP was more sensitive than the ESR also for polymyalgia rheumatica (PMR) diagnosis (Cantini F, Salvarani C, Olivieri I, Macchioni L, Ranzi A, Niccoli L, et al. Erythrocyte sedimentation rate and C-reactive protein in the evaluation of disease activity and severity in polymyalgia rheumatica: a prospective follow-up study. Semin Arthritis Rheum 2000;30:17–24.) Elevated CRP levels should be in the diagnostic work-up of PMR/GCA, especially in those patients with a normal ESR.

Carlo Salvarani MD*, Gene G. Hunder MD†, * Rheumatology Service, Arcispedale S. Maria Nuova, Reggio Emilia, Italy, † Mayo Clinic, Rochester, MN