Instructions for IBS-80 Food Patch Testing
Before Applying the Patches:
Instruct the patient to avoid direct sun exposure on the back for four weeks before the patch tests are applied. A suntan may decrease the skin's ability to mount an immune response to the test materials. Individuals with hair on their upper and mid back should shave it off two days before their appointment. Instruct them not to use chemical hair removers. Have the patient take a bath or shower the morning of the first appointment but instruct them not to apply any lotions or other products to their back after showering.
Gown the patient from the waist up with the opening in the back. Women should remove their bra but can put it back on once the patches are in place.
Gently wipe the back with isopropyl (rubbing) alcohol, let dry, then apply the patches. After the patches are applied, instruct the patient to take a tub or sponge bath only, avoid excessive sweating, and avoid bending the back too much for the next two days so that the patches stay in place.
Remove patches from the back, wipe off any allergen debris with an isopropyl alcohol pad, and outline the patch positions on the back with a suitable marking pen. Perform the 48-hour patch test reading and record the results on the provided Data Collection Form. Instruct the patient to bathe as usual except to avoid directly washing the back until after the final patch test reading, which is 1 or 2 days later. This will help ensure that the patch positions remain visible for the last reading.
Perform the final reading, record the results, and generate Food Avoidance Information (LINK TO FAI COMING SOON) based on the patient's results. Include the allergens that caused just a questionable reaction, as these are sometimes relevant.
Review the avoidance information with the patient, giving instructions to avoid all foods in question for one month and, if helpful, indefinitely. If there is improvement after a month and some of the patch reactions were just questionable, rechallenging one at a time with those that were questionable may be worthwhile. If symptoms recur, eliminate these foods again from the diet.
The pen markings may be removed with gentle isopropyl alcohol cleansing or will slowly fade away with normal bathing. Any pruritic reaction sites may be treated with a mid- or high-potency topical corticosteroid cream for a few days. The difficulty of adhering to the patch test-guided avoidance diet will depend on the number of allergens and the ubiquity of each specific allergen. Some are harder to avoid than others. Depending on the complexity of the avoidance, referral to a dietitian may be helpful.