The potent allergen that's soaking into millions of graying heads

About seven years ago, Terri Domsky feared she had to choose between not dyeing her gray hair or dying.

Taking a slug of Benadryl was no longer enough to combat the itchy red scalp that followed a trip to the hair salon.

"One day," recalled the 54-year-old Queen Village resident, "I left the hairdresser, and my hands and feet swelled. The base of my neck swelled. I had rashes. It scared the crap out of me. I went to a dermatologist who gave me steroids. Basically, he advised me that I had a PPD allergy and I could develop anaphylactic shock and die."

PPD, or paraphenylenediamine, is the world's most popular oxidative hair dye agent, used in about two-thirds of professional and do-it-yourself hair-coloring products on the market. It's also a nasty allergen with a checkered history going back 150 years.

If PPD were invented today, it probably wouldn't be permitted in cosmetics, experts say. But U.S. and European regulators allow the chemical in hair dye — in limited concentrations — and manufacturers keep using it because they don't have a perfect substitute. When combined with an oxidizer such as hydrogen peroxide, PPD penetrates the hair to produce lasting, lustrous, natural-looking hair color.

After learning all this, Domsky, a Philadelphia assistant district attorney with a passing resemblance to the actress Debra Winger, envisioned an embarrassing reveal: "I was like, 'What am I going to do? How do you grow it out? How do I try court cases with skunk scalp?' "

As she discovered, there are ways to ease the transition to au naturel, as well as a variety of PPD-free hair dye options.

About 5 percent of dermatitis patients test positive for PPD allergies on skin patch tests, studies show.

That small percentage translates to a huge number because these days, color-enhanced hair is ubiquitous, from purple-streaked punks to blond octogenarians. Most are women, but surveys suggest about 11 percent of men over age 50 also color their hair.

"PPD is widely used and most people aren't allergic to it. But when they are, PPD tends to be a very potent allergen," said University of Pennsylvania dermatologist Bruce Brod. He is past president of the American Contact Dermatitis Society, which voted PPD "Allergen of the Year" in 2006.

Reactions that begin as skin irritation, called dermatitis, can worsen with repeated exposure, causing swelling, hives, and, in rare cases, the life-threatening immune overreaction known as anaphylaxis.

The U.S. Food and Drug Administration requires PPD-containing products to warn consumers to do a preliminary skin test, and not to dye the eyelashes or eyebrows.

Those precautions belie a colorful history.

In the mid-1800s, German chemists figured out that coal tar — a thick, smelly, brown waste liquid produced by burning coal — contained useful chemicals. One of them, PPD, became a staple dye of the textile industry. Today, PPD is a petroleum derivative.

PPD was first used to dye hair in the late 1800s. Oscar Wilde — whose morality novel about vanity, The Picture of Dorian Gray, came out in 1890 — is believed to have been a fan. And allergic.

"To maintain his own youthful looks, it is reported that Wilde frequently dyed his graying locks," Loma Linda University dermatologist Sharon E. Jacob wrote in an article about PPD. "It is also reported that he suffered odd ailments such as pus-filled ear infections and an unidentified skin disease."

Eugene Schueller, a French pharmacist and entrepreneur, turned PPD into a coiffure cash cow with the 1909 founding of  the French Harmless Hair Dye Co. He later changed the name to a made-up word now known worldwide: L'Oreal.

In 1930s, PPD-laden eyelash and eyebrow dyes became popular. After "Lash Lure" blinded a woman who had plucked her eyebrows and got a staph infection, President Franklin D. Roosevelt's administration used the disaster to help win passage of a 1938 law that, for the first time, gave the FDA authority over cosmetics.

Occasional disasters continue. "Black henna" temporary tattoos — illegal mixtures of henna and PPD — can cause dreadful skin reactions. (The FDA warning page shows examples.) In a few cases, unsuspecting women who then dyed their hair, sometimes years after getting tattooed, died of anaphylactic shock, a sudden, severe immune system overreaction.

So what's an allergic woman (or man) to do?

If you suspect you have a PPD allergy, Brod recommends seeing a dermatologist who can do a skin patch test to make a definitive diagnosis, and also check for allergies to dyes that are chemical cousins of PPD. He uses an American Contact Dermatitis Society product database, available to member physicians, to guide patients to alternatives to PPD hair dyes.

PPD-free hair dyes fall into five main categories, each with limits and caveats, experts say:

Domsky found her way with the help of Juliene Featherman, founder of JuJu Salon & Organics, a Queen Village salon that specializes in using hair coloring free of ammonia and PPD.

First, they tried cutting Domsky's hair short and adding blond highlights to minimize the striped effect as her natural gray grew out.

"It looked good, and I like having short hair, but it just wasn't me," Domsky said.

So Featherman did some research and found Elumen, a dye made by Goldwell, a German-based maker of professional hair products. The company says it uses an acid and other proprietary "penetration enhancers" to get colors to go beneath the hair surface.

"It took a couple months to get the right formula down," Domsky recalled. "In the store, my hair looked brown, but in the sunlight, it looked purplish. Now it's great. It's been a couple years without a rash or a bump and I haven't had to go gray. It costs more and the color fades a bit with washing, but I'm OK with that."

Clairol, the company that unveiled the first use-at-home PPD-based coloring kit in 1956, ran ads playing on women's fear of aging and ageism, calling gray hair "the heartless dictator."  Now and then, Domsky thinks about the psychology of hiding a measure of her age.

"You feel a little vain," she said.  "But you wear your hair every day. It gives you self-confidence."

Mary Cossard, 55, of Princeton, an insurance industry professional, echoed that. She toughed out her worsening PPD allergy for years, even taking prednisone left over from a prescription written for her dog. Finally, she went to Brod, who offered a list of safe products, including a henna-based dye and the one she opted for, Elumen.

"It's not just a vanity thing," said Cossard, a self-described caramel blond with red and brown overtones. "If you look better, you feel better. We all want to look vibrant and fresh and perfect."