Top 10 contact dermatitis allergens identified

Sometimes the cure is another allergen

Among the top ten most common causes of allergic contact dermatitis are some of the topical steroids often used to treat the condition, according to a Mayo Clinic dermatologist.

A study by Mayo researchers led by Mark Davis, MD reveals the most common causes of the swollen, reddened, and itchy skin that is the hallmark of contact dermatitis are:

  • Nickel (nickel sulfate hexahydrate), metal frequently encountered in jewelry and clasps or buttons on clothing;
  • Gold;
  • Balsam of Peru (myroxylon pereirae), a fragrance used in perfumes and skin lotions, derived from tree resin;
  • Thimerosal, a mercury compound used in local antiseptics and in vaccines;
  • Neomycin sulfate. a topical antibiotic common in first aid creams and ointments, also found occasionally in cosmetics, deodorant, soap, and pet food
  • Fragrance mix — the eight most common fragrance allergens found in foods, cosmetic products, insecticides, antiseptics, soaps, perfumes, and dental products;
  • Formaldehyde, a preservative with multiple uses, (e.g., paper products, paints, medications, household cleaners, cosmetic products, and fabric finishes);
  • Cobalt chloride, a metal found in medical products, hair dye, antiperspirant, objects plated in metal, and cobalt blue pigment;
  • Bacitracin, a topical antibiotic;
  • Quaternium-15, a preservative found in cosmetic products such as self-tanners, shampoo, nail polish, and sunscreen, or in industrial products such as polishes, paints, and waxes.

While contact dermatitis is in most cases an annoyance, in some cases, it interferes with daily life. "Patients with contact dermatitis can get a very itchy rash from head to toe, or in a confined area," says Davis. "If it's on the hands and feet it can be disabling, and patients at times can't do their jobs."

The study confirms that patch testing is a useful means of identifying common allergens.

Avoidance of the allergen is the best — and sometimes easiest — treatment for contact dermatitis, says Davis. For example, if the nickel coating on the snap at the waistband of an employee's jeans is causing an itchy spot where it touches skin, it (the snap) can be covered with adhesive tape to prevent contact. Soaps that irritate skin can be replaced with hypoallergenic versions.

Corticosteroid creams sometimes are used to treat the rashes that accompany dermatitis; however, the study revealed that some patients with contact dermatitis are also allergic to the topical steroids.

EPA cautions against ionic air purifiers

Devices create smog-comparable ozone emissions

If some employees at your work site are using ionic air purifiers in their work areas in hopes of ridding the air of impurities and allergens, they might actually be adding something undesirable — levels of ozone that exceed safe levels.

California's Air Resources Board has declared war on the devices, saying they create ozone conditions that exceed those in Los Angeles on its smoggiest days.

"People operating air purifiers indoors are more prone to being exposed to ozone levels in excess of public health standards," according to Sergey Nizkorodov, PhD, a chemistry professor the University of California, Irvine who led a study into the effectiveness and health effects of the air purifiers. What his team found is that used in confined spaces, the purifiers may do more harm than good.

Ionic air purifiers are said to work by charging airborne particles and then attracting them to metal electrodes. They emit ozone as a byproduct of this ionization process.

Indoor air purifiers have gained quick popularity in response to public concerns about air quality, asthma, and allergens. Some purifiers produce ozone intentionally, purportedly as a "magnet" for impurities such as dust and pollen, while in others, ozone is a byproduct of its ionization process. But ozone is recognized as an air pollutant, one that regulated by federal and state standards.

Manufacturers claim that the purifiers produce harmless levels of ozone, but according to Nizkorodov, ozone has no effect on most pollutants, kills mold only at very high levels, and can actually cause increases in some pollutants, such as formaldehyde.

Exposure to high levels of ozone can damage the lungs, cause shortness of breath and throat irritation, and exacerbate asthma. It inflames and irritates respiratory tissues, and causes coughing and chest tightness. Ozone is the primary component of smog, and has been recognized and regulated as a serious outdoor pollutant for many years.

The EPA, which has monitored the devices for some time, has issued advisories discouraging use of the ionic purifiers, pointing out in one bulletin, "Scientific evidence shows that at concentrations that do not exceed public health standards, ozone has little potential to remove indoor air contaminants."

Even the claim that the purifiers eliminate odors from the air is questionable, the researchers say; ozone has been shown to "fatigue" the olfactory sense and reduces the ability to smell odors, and thus masks odors, rather than removing them.

The California Air Resource Board has additional information on air purifiers at its web site: