Cosmetics May be Sources of Contact Hypersensitivity
Ingredients commonly used in topical pharmaceuticals and cosmetics may be sources of contact hypersensitivity in patients with chronic eczema. Certain ingredients in topical pharmaceutical agents and cosmetics might cause skin reactions in people who have eczema.
The biggest offender was the preservative thimerosal, as 11% of the patients demonstrated sensitization to the substance.
To identify some of the key sources of contact sensitivity, investigators conducted patch tests in 2,218 patients with chronic eczema, 1,531 of whom were women. The tests determined the patients' sensitivity to 29 ingredients (including preservatives, antioxidants, and emulsifiers) often found in topical pharmaceutical and cosmetic compounds.
Testing consisted of 48-hour exposure to test strips, followed by reaction-assessment at 48, 72, and 96 hours.
Other sources of sensitization in men included formaldehyde (3.2%), dodecyl gallate (2.9%), phenylmercuric acetate (2.3%), chloracetamide (1.9%), and chlorhexidine (1.6%).
In women, the leading offenders included phenylmercuric acetate (2.8%), formaldehyde (2.0%), bronopol and kathon CG (1.9%), dibromodicyanobutane/phenoxyethanol 1:4 (1.8%), and chloracetamide, chlorhexidine, and dodecyl gallate (1.2% each).
If you are concerned with a product that you are considering buying, reading the label for ingredients will be helpful. However, some individuals sensitivity did not get expressed unless the affending chemical was 10% of more of the content of the product. It very well be that you need to use a product for at least two weeks before you can tell if you have sensivities to it.