To the Editor:—
No reports of local reactions to parenteral administration of vitamin B12 have come to my attention to date, although I have observed such an incident. The patient is a 47 year old, lean, white, ambulant woman who has had multiple radicular neuralgias for many years. Evidence of hypovitaminosis had been present even prior to cholecystectomy and posterior gastroenterostomy for chronic cholecystitis and duodenal ulcer in 1937. Doses of 7.5 micrograms of vitamin B12 (concentrate) were given subcutaneously in the right or left deltoid regions on March 17, March 24, April 18 and April 28, 1950, without undue effect. On May 17, she received 10 micrograms in the left arm, which was followed by pronounced swelling and pain in the arm lasting several days. On May 22 the same dose in the right arm produced a similar effect. No general effects were noted by the patient.