Allergist Matthew Zirwas from Ohio State University Medical Center comments:
Unlike other food allergies, nickel doesn't cause a fast reaction. "It's not like a normal allergy to, say, peanuts. Where, if you look and say a kid is allergic to peanuts. If he eats a peanut, 30 seconds later, his whole body is swelling up, he's having a severe reaction. With this kind of allergy, it's much more the cumulative effect of the nickel we eat." The most common sign is an itchy, painful rash on the outside of the elbow or the palms.
About 15% of Americans have skin that's sensitive to nickel in jewelry, watches, and clothing.
How do you test for contact dermatitis?
The most established test for contact dermatitis is skin patch testing. The patient is advised to take a shower the day before the test. Two patches are placed on the back. The patient should not take a bath of the whole body until test is read 48-72 hours later.
The patient should remove the patch at home before driving to the clinic. This time period of 30-60 minutes allows the surrounding nonspecific erythema (from the patch) itself to subside. The test area should be examined again 72-96 hours later to detect any delayed skin reaction.
A commercially available kit is the thin layer rapid use epicutaneous test (T.R.U.E. Test). The T.R.U.E. test manufacture website provides useful patient information handouts on avoidance of specific contact allergens.
Rise in nickel food allergies. ABC News.
Allergic skin diseases. Luz S. Fonacier, MD, Stephen C. Dreskin, MD, PhD, Donald Y.M. Leung, MD, PhD. The Journal of Allergy and Clinical Immunology, Volume 125, Issue 2, Supplement 2 , Pages S138-S149, February 2010 (PDF).
Comments from Twitter:
Dr Melinda Rathkopf @mrathkopf: Rise in Nickel Food Allergies - I have been looking into this more. Interested in how other allergists discuss this. How do you treat/discuss this with your patients? When do you make the leap that dietary Ni may be involved?
Matthew Bowdish MD @MatthewBowdish: Honestly, it hasn't really been on my radar enough. I did have a pt with Ni allergy who did have many of these intolerances. Also, I do try to mention to those with known or discovered nickel sensitivity to see if they've had sxs.