Avoidance is prevention for both allergic contact dermatitis and irritant contact dermatitis. On the other hand, there are certain precautions that can be taken to prevent exposure to either irritants or potent allergens. Protective clothing can be quite helpful. There are certain so-called "barrier creams" that may be more or less useful in limiting contact to irritants and possibly allergens. In the case of poison ivy , oak, or sumac, application of barrier creams has been shown to be of use prior to exposure (Stokogard, Hollister Moisture Barrier, and Hydropel are brand names of somewhat effective creams) when available.
Paraphenylenedeamine (PPDA) is an ingredient found in permanent hair dyes. This ingredient is mixed with an oxidizing agent, such as peroxide, before application. People allergic to PPDA should not use any permanent hair dyes. About one fourth of the people allergic to PPDA are also allergic to ingredients in semi-permanent dyes. Follow the package instructions for a patch test before using any hair dye. Most PPDA allergic people can use temporary dyes or rinses, to blend in gray and brighten hair. A few people, however, will react to these dyes also.