A systematic review of allergic and irritant contact dermatitis of the vulva: The most important allergens/irritants and the role of patch testing.

Vulvar allergic contact dermatitis (vACD) and irritant contact dermatitis (vICD) are common and accompanied by a great burden on the patient's life. We aimed to review the existing literature on vACD and vICD in order to provide a comprehensive reference list of potential vulvar allergens and irritants, as well as to establish the role of patch testing therein. A systematic search was performed in Medline, Embase and Web of Science using a search string based on the PICO-format. The study protocol was registered at PROSPERO (CRD42021239527). Multiple allergens were identified and included metals, topical drugs, fragrances, preservatives, cosmetic constituents and rubber components. Not all positive reactions were, however, considered to be relevant. Patch testing is the primary tool for the identification of the causal allergens. Testing with standard series alone was proven to be insufficient. Little information about irritants was found. In the future, additional series and late readings should be considered in standard practice. Studies on vICD are scarce and further research is necessary. More population-based research should be performed.