Skin patch testing to guide food avoidance in irritable bowel syndrome

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with irritable bowel syndrome (IBS). They get skin patch tests to 80 foods and food additives. People found to have food allergies then follow an avoidance diet for 16 weeks.

Age

18 years and older

Sex

All sexes

Disease stage

IBS diagnosed by a primary care provider, gastroenterologist or allergist, or IBS that meets the Rome IV criteria with symptoms that are poorly controlled.

Earlier treatment

No cortisone-containing or immune-suppressing medicines (such as cyclosporine, mycophenylate mofetil, azathioprine, tacrolimus) within two weeks before patch testing or during the study. IBS medicines must not have been started or changed within 30 days of joining. People must be willing to stop the low FODMAP diet from 1 week before the study.

Main reasons for not taking part

• Pregnancy
• Severe rash, severe allergy to adhesive tape, or back exposed to the sun in the 2 weeks before patch testing
• Celiac disease, cirrhosis, gut cancer, inflammatory bowel disease or diverticulitis active within the prior 2 years, or past gut surgery (except appendix or gallbladder removal more than 6 months ago)
• Poorly controlled psychiatric disease, such as severe depression, severe anxiety, schizophrenia or dementia
• Heavy alcohol use, illicit drug use, high-dose opiates, or not speaking English

The registry criteria, word for word

What the trial wants to find out

Participants with IBS are skin patch tested (no needles) to 80 different foods and food additives, compounded for patch testing, in search of food allergies. The testing requires 3 office visits within a 4 or 5 day period. The patches are taped to the back at Visit #. At Visit #2 48 hours later, the patches are removed from the skin and the outside border of each patch is marked with a felt tip marker. At Visit #3 (final visit) 1 or 2 days later, the patch test reading is performed by the doctor-investigator. An allergy is identified as a small red mark where the food was in contact with the skin for 48 hours. Those participants found to have food allergies are then placed on an avoidance diet (no calorie restriction) for 16 weeks where they either avoid eating the food(s) to which they are allergic (the \"true\" avoidance diet) or food(s) to which the testing did not show an allergy (this is called the \"sham\" avoidance diet). There is a 50/50 chance of going on either avoidance diet. The avoidance diet is assigned in such a way that neither the participant or the doctor-investigator knows which diet is being followed. After the 16 weeks, the participants answers a brief online questionnaire that asks about the IBS symptoms while following the avoidance diet. After the 16 week avoidance diet and final questionnaire are completed, those participants who were on the sham diet will be told of their true food allergies which they may try avoiding on their own.

The 2 groups in the trial

• True avoidance dietExisting treatment, for comparison

  Food patch test-directed avoidance diet for 16 weeks where participant avoids avoid eating the food(s) to which they are allergic

• Sham avoidance dietSham treatment, for comparison

  Avoidance diet for 16 weeks of randomly selected foods to which the patch testing did not show an allergy