Some parents may breathe a sigh of relief; even the most "permanent" dye job isn't as permanent as a tattoo, or a pierced lip or tongue.
But as more and more young people color their hair, the incidence of hair dye allergies is also increasing, warns a group of European dermatologists.
The culprit is a common chemical ingredient in permanent hair dyes, called para-phenylenediamine, or PPD. PPD is found in more than two-thirds of commercial dyes, the researchers say, including many of the top-selling brands.
Patients with severe PPD reactions commonly develop painful rashes around the hair line or on the face, which often require treatment and can occasionally lead to hospitalization. Facial swelling is also common.
Many Don't Seek Treatment
In his own London clinic, dermatologist John P. McFadden saw a doubling of PPD reactions over the past six years.
"Dermatologists report anecdotally that the frequency of positive reactions to PPD on patch testing is increasing," McFadden and colleagues write in an editorial published in the Feb. 3 issue of BMJ.
Last October, editorial co-author Heidi Sosted of the University of Copenhagen reported on eight cases of severe hair dye reactions among teens between the ages of 12 and 15.
Reactions were so serious that five of the teens had to be hospitalized, and one reportedly ended up in intensive care.
In an earlier study, Sosted and colleagues examined the frequency of hair dye reactions in a sample population of 4,000 adults living in Denmark.
A total of 18% of the men and 75% of the women said they had used hair dyes, and slightly over 5% said they had experienced allergic reactions to them. But only 15% of those who had allergic reactions reported seeking medical treatment.
"Wider debate on the safety and composition of hair dyes is overdue -- among medical and scientific communities, the public and legislators," McFadden, Sosted, and colleagues write in the BMJ editorial.
"Cultural and commercial pressures to dye hair and, perhaps, the widespread obsession with the 'culture of youth' are putting people at risk and increasing the burden on health services."
Hair Dyes 'Thoroughly Studied'
In a statement issued to WebMD in response to the editorial, the Cosmetics, Toiletry and Fragrance Association countered that hair dye is among the most thoroughly studied of consumer products and that safety tests on the individual ingredients that make up hair dyes are "continually updated."
"Just like many other products in common use, such as certain foods or drugs, hair dyes can cause skin allergic reactions in some individuals," CTFA officials write. "The number of consumers allergic to hair dyes is very small and the majority of these reactions occur at the site of contact many hours after hair dye use and resemble other contact-allergy reactions like nickel, poison ivy, etc."
First-time users can greatly reduce their risk of allergic reactions by conducting a skin-sensitivity test 48 hours before coloring their hair.
"The necessary warnings and instructions for skin testing are on hair coloring packages," notes the CTFA statement. "If a consumer is positively identified as allergic to a hair dye ingredient, they can (and they should) avoid use of all permanent hair dyes and consult a physician before any further use."
SOURCES: McFadden, J.P. BMJ, Feb. 3, 2007; vol 334: p 220. John P. McFadden, senior lecturer, St. John's Institute of Dermatology, London. "Severe Allergic Hair Dye Reactions in 8 Children," Contact Dermatitis, October 2006. "Contact Dermatitis to Hair Dyes in a Danish Adult Population: An Interview-Based Study," British Journal f Dermatology, July 2005.
By Salynn Boyles
Reviewed by Louise Chang