People with peanut allergy may also be allergic to lupin flour, which is increasingly being added to human food products, British investigators report in The Lancet medical journal.

Dr. Michael Radcliffe, at Royal Free Hospital in London, and associates report the case of a 25-year-old woman with known peanut allergy who developed a severe life-threatening allergic reaction after eating fried onion rings. Testing showed an allergic response to lupin.

During a call to the distributor of the onion rings, the patient was informed that the onion ring batter contained lupin.

Dr. Radcliffe’s group notes that “in 2002, lupin was the fourth most frequent cause of severe food-associated anaphylaxis reported to the French Allergy Vigilance Network.”

Because there appear to be cross-reactions between peanuts and lupin flour, they advise that anyone with peanut allergy should avoid products containing lupin until they can be specifically tested.

SOURCE: Lancet, April 9, 2005.