Contact Allergen of the Year: p-Phenylenediamine


by Vincent A. DeLeo, Medscape, 24 Oct 2006

p-Phenylenediamine, the allergen of the year? Why now?

Granted, p-phenylenediamine (PPD) has been the leading permanent hair coloring agent or oxidative hair dye in most of the Western world since its introduction in the 1880s,[1] and it has been a problematic agent almost since its debut. Because of its allergic potential, it was banned in France and Germany from 1906 until the 1980s to 1990s, when it was again allowed for use in member states of the European Union.

So why now?

PPD was chosen this year because a number of changes have occurred recently in the clinical aspects of dealing with allergy to this antigen. These include the recognition of new patterns of exposure that lead to increased sensitization potential; increased usage by women and even men of the "baby boomer" generation in an attempt to stave off the appearance of aging; a broadening array of cross-reacting substances; reports of high levels of sensitization in certain ethnic groups; and new substitutes that will likely allow those who are sensitive to continue to alter the color of their hair.

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