The erythrocyte sedimentation rate (ESR) is a frequently used but nonspecific indicator of inflammation or infection. Clinicians often check an ESR in patients with symptoms of headache, facial or jaw pain, and visual loss, as an aid in the diagnosis of temporal arteritis. We present two patients with these complaints, who did not have temporal arteritis, nor any other inflammatory condition or infection, but had ESRs near or above 100 mm/h, leading to diagnostic confusion. An occult nephrotic syndrome, with or without renal insufficiency, can cause such a highly elevated ESR, and was discovered in these patients.