Diazolidinyl Urea

Diazolidinyl urea is a preservative in cosmetic products, protecting them from bacteria, yeast, and mold growth. Although it is rare, preservatives can cause allergies and irritations in sensitive individuals.

Skin contact with diazolidinyl urea is required for it to cause a rash. Discontinuation of exposure to products containing diazolidinyl urea should result in improvement and/or resolution of your dermatitis. The most common cause of allergic contact dermatitis from diazolidinyl urea is cosmetics preserved with this chemical. By law, all products made in the United States for topical use have the ingredients listed either on the product package or the box that contains it, so check the labeling of ingredients in your cosmetics.

If there is not enough information, ask your retailer or pharmacist or contact the manufacturer directly. At work, request a Safety Data Sheet (SDS) to help identify potential sources of exposure.

Some individuals who are allergic to formaldehyde are also sensitive to diazolidinyl urea, since diazolidinyl urea releases small amounts of formaldehyde. Diazolidinyl urea sensitive individuals may also need to avoid products preserved with formaldehyde or formaldehyde-releasing agents, such as:

Here is a partial list of products known to have contained Diazolidinyl Urea in the past.