Temporal arteritis. A preventable cause of blindness.

Temporal arteritis is an uncommon condition but must be recognised early if complications such as blindness are to be avoided. The onset of daily headache or systemic disturbance with muscle and joint pains in patients over the age of 50 years should arouse suspicion. The ESR is usually greater than 40 mm an hour, but it is advisable to proceed to temporal artery biopsy if the story is typical even though initially the ESR may be normal. Histological confirmation is desirable because steroid therapy may have to continue for several years.