ROAT repeated open application

IgE Immunoglobulin E ROAT Repeated open application test... 

Clinical relevance of a positive patch-test reaction may exist for at least 55-65% of positive results. Strongly positive patch test reactions (2+ or 3+) are more likely to be associated with a positive fragrance history than a weak or doubtful reaction (Frosch et al. 1995b). A positive ROAT (repeated open application test, twice daily application on the antecubital fossa for a maximum of two weeks) (Johansen et al. 1996) with fragrance ingredients makes relevance of the reaction more likely. 

Patch tests in patients with anogenital eczema should include the standard series cinchocaine HCl, propolis, bufexamac, and other ingredients of topical formulations according to the patient s history. In cases of doubt, the repeated open application test (ROAT) is recommended. Patients should be advised to apply the suspected product three times a day for 3 days to an area of healthy skin on measuring 5 cm x 5 cm the flexural site of the forearm (35). 

Hannuksela M, Salo H. The repeated open application test (ROAT). Contact Dermatitis 1986 14(4) 221-227. 

Details of the performance of the repeated open-application test (ROAT) and its relevance are given in textbooks (Rietschel and Fowler 1995 Wahiberg 1995). 

The concentration of the allergen in the product may be too low to cause a positive response. Moreover, the allergen may not be liberated in sufficient quantity, or the occlusion may be insufficient, so that other testing methods might be required. In certain cases, repeated open-application tests (ROAT) (Hannuksela and Salo 1986) can be useful. With the semi-open test method (Dooms-Goossens 1995), it is possible to use undiluted chemicals, but the penetration may be too low to induce test reactions. If a product is under serious suspicion, the different ingredients should be tested individually. 

Information regarding test concentrations and vehicles are rarely available - for the examining dermatologist, the testing is a question of trial and error. If a positive reaction is obtained, it is crucial to carry out serial dilution tests and to test a sufficient number of controls (>25). So far, provocative use tests, such as the repeated open application test (ROAT), do not seem to have been used to clarify the relevance of a positive patch-test reaction to a solvent. 

Hannuksela and Hannuksela [152] compared the development of irritant reactions in a wash test in a repeated open application test (ROAT) and in a chamber test by using a hand dishwashing liquid. They showed that the results of the chamber test and of the ROAT do not accurately predict the results of the wash test. 

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