Experts explore link between allergies and interstitial cystitis

Jun 22 2009

Allergy testing and treatment may offer a new therapeutic option for many patients with interstitial cystitis (IC). IC is a severely painful bladder condition affecting as many as 8 million women and 1.5 million men in the United States. Patients and the providers who treat them have long noticed a correlation between allergies and IC.

Recently, a urologist and allergist in Louisville, Kentucky, began to explore the link between these two chronic ailments to provide patients with more effective treatment. The story of their discoveries is featured in the ICA Update, the quarterly magazine of the Interstitial Cystitis Association (ICA).

"Until now, the evidence linking IC and allergies has been circumstantial," said Barbara Gordon, executive director of the ICA, an organization providing advocacy, research funding, and education to ensure early diagnosis and optimal care with dignity for people affected by IC. "Epidemiologic studies show the prevalence of allergies in IC patients to be higher than in people in general. Anti-allergy medications seem to ease IC symptoms, especially when patients have seasonal allergies. And during allergy seasons, doctors report an upswing in IC-related calls and patient visits."

That suggests that there is a correlation between allergies and IC, but can allergies cause bladder symptoms? A clearer answer comes from actual allergy testing and treatment of patients. After holding several discussions on this subject, John Hubbard, M.D., a urologist, and C. Steven Smith, M.D., an allergist/immunologist, partnered to study this phenomenon in a more formal way.

These doctors found they were referring patients to each other. Hubbard was sending IC patients with seasonal allergies to Smith, and Smith had allergy patients who also had bladder symptoms. Then, they found that Smith's allergy testing and treatment was helping to resolve IC symptoms, sometimes dramatically.

Foods Fingered

Although IC patients' seasonal allergy miseries are what gave the clue to the connection, Smith is finding that food allergies are common in IC patients. He estimates that 35 to 40 percent of the IC patients he sees have bona fide allergies to foods, based on the results of their skin prick tests and elimination-challenge diets, and that their IC gets better when they remove those foods from their diet. "We've been able to identify a lot of food allergies that IC patients didn't even know they had," noted Heather Lange, ARNP, the nurse practitioner who works with urologist Hubbard's IC patients.

Stimulants, such as coffee and tea, and the acid and spicy foods that have long been known to cause problems for IC patients may be bladder irritants even without allergy. "Put those on already irritated bladder tissue, and you probably are going to see a response," Smith said. But he's also finding allergic reactions to some of these items in IC patients. Positive skin prick tests for cayenne (a hot pepper) seem to be common.

The effect on IC of treating environmental allergies with shots or medications is less obvious, said Smith, but still seems to be beneficial. About half to a third of the IC patients he sees have proven environmental allergies or symptoms, such as hay fever, asthma, recurrent ear infections, or chronic urticaria (hives).

Hubbard and Smith are collaborating on a more formal study of the link. One goal is to find a marker that will help urologists decide which patients may benefit from allergy testing and treatment. Like many urologists, Hubbard uses cystoscopy and hydrodistention under anesthesia as part of his workup to exclude other conditions that may cause IC-like symptoms. But he is reviving an older practice of taking a biopsy specimen during the procedure and sending it to a pathologist to look for mast cells because, when mast cells reach a certain density, patients seem to benefit from allergy testing and treatment. Mast cells elsewhere in the body are key players in allergic reactions, but their role in the bladder tissue of IC patients has not been clear.

Dr. Smith and Dr. Hubbard plan to conduct more research and hope to spark the interest of additional IC and allergy researchers. Meanwhile, these doctors are continuing to help IC patients get better. Not everyone responds, said Smith, "But for the high percentage who do improve with allergy management, it's well worth the effort. It's one of the most rewarding patient care experiences I have ever had."

Diet and IC

Future research will reveal more about the role of food allergy in IC patients' symptoms. Meanwhile, whether patients have "true" allergies or sensitivity to foods, the treatment is the same -- an elimination challenge diet. Elimination diets remove the potential problem foods from the patient's diet and add them back one at a time to see if the food really causes a problem.

ICA offers the following advice to patients when modifying their diets: -- The effect of food and drinks on IC symptoms varies greatly from individual to individual. It's important to note the type of food or beverage, as well as how much, how often and the specific combination of food and beverages ingested. Give yourself plenty of time to discover your ideal diet. It may require several weeks of trial and error. -- Eat a healthy, varied, balanced diet -- most patients can do this if they work to identify problem items first.