Common scents: Fragrances trigger contact dermatitis

April 30, 2009

Cosmetic products, such as preservatives or fragrances, can contain ingredients that elicit allergic reactions in patients. In some instances, dermatologists may not be patch testing with sufficient concentrations to detect allergens.

Leuven, Belgium - Cosmetic products contain ingredients, such as preservatives and fragrance components that trigger allergic reactions in patients, according to An E. Goossens, Ph.D., a pharmacist and a professor at the University of Leuven in Leuven, Belgium.

Dr.Goossens says many chemicals with anti-microbial properties are chemically reactive and produce sensitization. "The more chemically reactive they are, the more they can produce sensitization," says Dr. Goossens, "Preservatives have to be chemically reactive if they are efficacious as preservatives."

Products such as deodorants contain also fragrances that put individuals at risk of having an allergic reaction, according to Dr. Goossens. "Deodorants often cause reactions, because they are applied to occluded areas where the allergens penetrate more easily into the skin," Dr. Goossens says. "They can also penetrate the hair follicle, which acts as a reservoir."


Study results

In a study published in Contact Dermatitis earlier this year, Dr. Goossens and colleagues concluded that fragrance contact allergy is common in patients suffering from contact dermatitis. Investigators examined results of patch testing in more than 10,000 patients and found that 380 males, and 1,083 females reacted positively to at least one fragrance-allergy marker in the standard series.

Specifically, 9 percent reacted to fragrance mix I, 6 percent to myroxylon pereirae; 4.8 percent, to colonphonium (often in association); 2.1 percent, to hydroxyisohexyl 3 cyclohexene carboxaldehyde or Lyral; and 2.1 percent, to fragrance mix II.

The hands and face were the most commonly affected body sites, and a significant association was found between specific fragrance allergens and certain locations.


Insufficient concentrations

When clinicians do patch tests, they may not be patch testing with sufficient concentrations to detect allergens, Dr. Goossens tells Dermatology Times.

"When you test, for example, the preservative mixture of methylchloro- and methylisothiazolonine at 100 ppm, you may miss allergy to it, and a test concentration of 200 ppm might be better," she says. "With most ingredients, you need to use much higher concentrations for patch testing than the actual use concentrations. When you use a cosmetic on the skin, the concentrations can indeed reach a higher level in the skin after a few days of use, due to cumulative effects."


Common culprits

Despite the increase in the use of sunscreens, their contribution to cosmetic allergy seems relatively small, although certainly not adequately investigated, according to Dr. Goossens.

She says that there have been cases of photoallergic contact dermatitis also from the new sunscreens octyl triazone and particularly octocrylene. Interestingly, a large number of emulsifiers, emollients and humectants are also increasingly being reported as cosmetic contact allergens.

While "natural" ingredients have become popular, they can provoke a reaction in subjects with sensitivities to fragrances. Indeed, there can be cross-reactivity between fragrances and plants because they share ingredients. Additionally, nonreactive chemicals, such as copolymers and esters, can provoke contact allergy.


Babies

Most recently, allergic reactions to baby wipes have been reported in both children and adults who use the products, with adults having developed an allergy on their hands.

"I don’t think that most pediatricians and also perhaps some dermatologists consider the possibility of contact allergy with this product," she says.

Dermatologists would find more allergens in infants when performing patch tests more frequently, since contact allergy occurs more frequently than expected. &334Sometimes there is also the reluctance on the part of parents to have their infants tested," Dr. Goossens says.

It’s best that parents use a solid soap rather than a liquid soap when bathing a baby, Dr. Goossens says.


Black henna

While regulations in Europe state that para-phenylenediamine (PPD) should be at maximum concentration of 6 percent in products such as hair dye, the concentration far exceeds that in a “black henna” tattoo, which illegally may contain up to 25 percent PPD.

"Henna itself is rarely sensitizing. Patients get sensitized because of the content of PPD or related dyes," Dr. Goossens says. DT