IBS Skin Patch Test Food Allergy Study

Inclusion Criteria: 1. Irritable bowel syndrome diagnosed by a primary care provider, gastroenterologist or allergist; or 2. meeting the Rome IV IBS diagnostic criteria by history and having suboptimally or poorly controlled IBS symptoms. Exclusion Criteria: 1. Under age 18 years 2. Pregnant 3. Severe rash 4. Receiving any cortisone-containing or any of the following immunosuppressive medications within two weeks prior to patch testing or plan to do so any time during the study: cyclosporine, mycophenylate mofetil, azathioprine, tacrolimus or others within these classes of medications) 5. Incapable of completing all parts of the 18-week screening period and study, including following the dietary instructions and completing all text or email questionnaires 6. Exposure of back to the sun in the 2 weeks prior to patch testing Unable or unwilling to discontinue the low FODMAP diet, if relevant, starting 1 week prior to the study and for the study duration 8\) Refusal to shave back hair, if relevant 9) Receiving pharmacologic therapy for IBS that has been started or changed within 30 days of study enrollment 10) Non-English speaking 11) Unable to provide written informed consent 12) Have a history of gastrointestinal disease including celiac disease, cirrhosis, gastrointestinal malignancy, inflammatory bowel disease, or diverticulitis, active within the prior 2 years. 13) Have a history of gastrointestinal surgery (except appendectomy and cholecystectomy or gallbladder removal \>6 months ago) 14) Have poorly controlled psychiatric disease such as severe depression (with or without suicidal ideation), severe anxiety, schizophrenia, dementia 15) Have excessive alcohol intake (more than 1 drink per day for females and 2 drinks per day for males) 16) Use illicit substances 17) Use high-dose opiates 18) Severe allergy to adhesive tape