Hair color is an important part of one’s identity. However, hair dye allergic contact dermatitis remains a problem for many; its prevalence among patients is reported as 4.3% in Asia, 4% in Europe and 6.2% in North America. P-Phenylenediamine (PPD) is a common ingredient and sensitizer in oxidative hair dye products that can lead to contact allergy dermatitis. While this is thought to be the most common sensitizer, there are more than 100 permitted chemicals in hair dye, and many have been identified as possible sensitizers. As a result, it is difficult prior to patch testing to determine which ingredient is causing the reaction.
Here, the authors describe the typical presentation and symptoms resulting from hair dye allergic contact dermatitis. Common chemical sensitizers in hair dye and the utility of patch testing are detailed, and interventions and prevention principles for those who wish to continue dyeing their hair are outlined—with clear implications for those formulating these product types.
The time course for developing dermatitis varies from hours to days following the dye exposure. Dermatitis symptoms commonly include itching, burning and a rash localizing to the face or scalp margins. It is important to note that the exposed scalp often fails to demonstrate visible inflammation. The presentation and dermatitis severity ranges from redness, subtle swelling and irritation of the eyes to intense swelling of the face with exudation of the scalp.