SOS Allergo · I understand & manage
ROAT: testing a product through repeated applications
Repeated Open Application Test — instructions for use
Why is this test used?
A ROAT involves repeatedly applying a product to a small area of healthy skin to see whether it gradually reproduces eczema. It may complement patch tests and help determine whether a product is genuinely relevant in your situation.
In this sheet
To complete on the PDF sheet
- Patient
- Product / brand / reference
- Start date
- Prescribed method
Instructions for use
1 — Mark out a small area
On healthy skin, draw a square measuring about 3 × 3 cm on the inner forearm or on the area indicated by your doctor.
2 — Use only the prescribed product
Apply only the product specified by the team, exactly as instructed: leave it in place, rinse it off after a specified time or use it at the prescribed dilution.
3 — Repeat the application
Unless instructed otherwise, apply the product morning and evening to the same area for the prescribed period, often 8 to 10 days.
4 — Observe the test area
If a reaction appears, take a clear photograph if possible and note the day and the approximate number of applications already completed.
Stop the test and contact the team if a reaction appears
Marked redness, severe itching, spots or blisters, a reaction resembling your usual eczema, or spread beyond the test area. Never deliberately intensify the test. Do not carry out a ROAT on your own with acrylates or methacrylates, corrosive or industrial products, or products of unknown composition.
How is a ROAT interpreted?
A positive ROAT supports the product’s responsibility. A negative ROAT makes responsibility less likely but does not always rule it out on its own. The final interpretation must consider the context, patch-test results and product composition.
Instructions from the team
- Duration in days
- Applications per day
- Next appointment
- Doctor / team
- Contact
SOS Allergo resources
Main references
- ESCD Guideline for Diagnostic Patch Testing, update 2026. Contact Dermatitis.
- Kaliyadan F, et al. Postepy Dermatol Alergol. 2022;39:304-306.
- Hannuksela M, Salo H. Contact Dermatitis. 1986;14:221-227.