Josh struggled for more than a decade with what his doctors had told him was irritable bowel syndrome (IBS). But curiously, the 39-year-old’s flare-ups were caused by some foods that aren’t typical IBS triggers.
So, Josh (not his real name) sought the care of New York gastroenterologist Yevgenia Pashinsky, MD. She conducted a comprehensive nutritional assessment and sent him for allergy testing. The results: Josh had a little-known condition called systemic nickel allergy syndrome (SNAS), which can mimic some of the symptoms of IBS.
Dr. Pashinsky, of the department of medicine at Icahn School of Medicine at Mount Sinai, New York, and a partner with New York Gastroenterology Associates, presented Josh’s case as part of a seminar on SNAS and IBS “mimickers” at the Food and Nutrition Conference and Expo in Orlando last October, sponsored by the Academy of Nutrition and Dietetics.
She and two registered dietitians in her practice, Suzie Finkel, MS, RD, CDN, and Tamara Duker Freuman, MS, RD, CDN, told seminar attendees that SNAS is rarely diagnosed and can be mistaken for IBS. They noted that it probably strikes more people than doctors suspect.
“Systemic nickel allergy is present in at least 10% of the U.S. population (and much higher in some subgroups),” Dr. Pashinsky told this news organization. “But its connection to GI symptoms and functional GI disorders is still being learned about.
“I think of nickel allergy and other allergic disorders when, in addition to GI symptoms, the patient reports skin and mucous membrane involvement along with their abdominal reactions,” she said.
For patients like Josh with SNAS, the diagnosis and treatment of this condition are surprisingly simple and effective.
“Josh had these really [unusual] symptoms and nontraditional IBS food triggers,” Ms. Finkel said in an interview. “So, that’s a situation where, as dietitians we say, ‘Hmm, that’s weird; if you have IBS, then peanuts and shrimp shouldn’t really cause an issue here.’ But this might be something physicians might not be attuned to because it’s not part of their training.”
Ms. Finkel said that Josh was referred to an allergist. Josh tested positive for skin sensitization to nickel, and he was started on a low-nickel diet, which improved his symptoms.
“So, that was this happy ending,” she added.
The upshot?
“Doctors who treat IBS patients [who are not responding to treatment] need to consider the possibility that they have SNAS and send them for allergy testing,” Ms. Finkel said. “If they come back positive, simple dietary changes can address it.”
An underrecognized condition
There has been very little research regarding SNAS in patients with IBS, and there are no standard guidelines for diagnosing and treating it.
What’s more, many gastroenterologists aren’t familiar with it. More than a dozen gastroenterologists who were contacted for comment declined to be interviewed because they didn’t know about SNAS – or enough about it to provide useful information for the story.
Ms. Finkel said she’s not surprised that many gastroenterologists don’t know much about how SNAS can mimic IBS, which is why she and her colleagues presented the seminar last October in Orlando. “It’s really an allergy and not a GI disease. It manifests with GI symptoms, but the root is not in the digestive tract; the root is in a true allergy – a clinical allergy – to nickel.”
Complicating the issue is that people who have IBS and those with SNAS typically share some common symptoms.
Like IBS, SNAS can cause GI symptoms – such as cramping, abdominal pain, heartburn, constipation, gaseous distension, and mucus in the stool. It can be triggered by certain fresh, cooked, and canned foods.
But the food triggers that cause SNAS are not usually those that cause IBS symptoms. Rather, SNAS flare-ups are nearly always triggered by foods with high levels of nickel. Examples include apricots, artichokes, asparagus, beans, cauliflower, chickpeas, cocoa/chocolate, figs, lentils, licorice, oats, onions, peas, peanuts, potatoes, spinach, tomatoes, and tea.
According to the American Academy of Allergy, Asthma & Immunology, a distinguishing feature of SNAS is that it can cause allergic contact dermatitis when a person touches something made with nickel. Coins, jewelry, eyeglasses, home fixtures, keys, zippers, dental devices, and even stainless-steel cookware can contain allergy-triggering nickel.
What Ms. Finkel sees the most are skin reactions from touching a surface containing nickel or from ingesting it, she said.
The other immediate symptom is abdominal pain or changes in bowel movements, such as diarrhea, she added.
Christopher Randolph, MD, an allergist based in Connecticut, told this news organization that it’s important for doctors to realize that patients who have a skin reaction to nickel may also have inflammatory GI symptoms.
“We definitely need more controlled studies,” said Dr. Randolph, of the department of allergy and immunology at Yale University, New Haven, Conn. “But the takeaway here is for patients and certainly providers to be mindful that you can have systemic reactions to nickel, even though you implicate only the contact dermatitis.”