OBJECTIVES To assess the clinical features of biopsy proven and negative biopsy temporal arteritis at the time of diagnosis and during a three year follow up.

RESULTS Two hundred and seven biopsy proven, and 85 negative biopsy cases were included from 1991 to 1997. Fifty eight per cent of the biopsy proven cases, compared with 39.29% of the negative biopsy cases, were diagnosed during the autumn or winter (p = 0.003). Visual problems (31.5%,v 19.1%, p = 0.031), blindness (9.7%v 2.38%, p = 0.033), jaw claudication (40.8%, v 28.243%, p = 0.044), and temporal artery palpation abnormalities (61.3%v 29.5%, p = 7.10^-7) were more frequent in the biopsy proven than in the negative biopsy group. Less specific symptoms, such as headache (82.5%v 92.9%, p = 0.021), or associated polymyalgia rheumatica (40.1% v 65.9%, p = 9 × 10^-5) were more prevalent in the negative biopsy cases. Biological markers of inflammation were significantly more increased in the biopsy proven group. All cases of blindness occurring after treatment belonged to the biopsy proven group.

CONCLUSION Biopsy proven cases seem to be more severe than biopsy negative cases at the time of diagnosis and during follow up. Seasonal difference at diagnosis may suggest a different aetiological pattern.