Allergic Contact Dermatitis: Topical Preservatives, Part I

J. Desiree Douglas


Dermatology Nursing 

In This Article


Synonyms for Formaldehyde

  • Methanal

  • Formalin

  • P-Formaldehyde

  • Oxymetholone

Formaldehyde was the seventh most common allergen causing ACD in patch test patients in 2005–2006 (Zug et al., 2009). It is the second most common cause of hand ACD and cosmetic ACD (Scheman et al., 2008; Warshaw et al., 2007). Women are affected 1.2–1.5 times more by a formaldehyde allergy than men; however, occupational sensitization usually affects more men (De Groot, Flyvholm, Lensen, Menne, & Coenraads, 2009).

Formaldehyde is not only a preservative, but it also serves as a disinfectant. It is created by natural sources; as it is released from incomplete combustion and burning of wood, tobacco, kerosene, coal, charcoal, and gasoline (Marks et al., 2002; Scheman et al., 2008). It is also found in instant coffee, aspartame, cod fish, caviar, shiitake mushrooms, smoked ham, and maple syrup (De Groot et al., 2009; Scheman et al., 2008).

Many occupations are affected by formaldehyde, causing cases of both irritant and allergic contact dermatitis. When dealing with occupational dermatitis, the top source of formaldehyde is metalworking fluids. The next most common sources of formaldehyde include liquid soaps, handwashing materials, shampoos, dishwashing liquids, detergents, and other rinse-off products. These cleansing items are actually common to occupational and non-occupational cases of formaldehyde sensitivities (Aalto-Korte, Kuuliala, Suuronen, & Alanko, 2008).

Specific occupations affected by formaldehyde allergies include machinists exposed to metalworking fluids, painters, photographers, maintenance workers, cosmetologists, embalmers, and housekeepers. Laboratory technicians, hemodialysis nurses, and other health care workers are also at risk for occupational sensitization (Maier, Lampel, Bhutani, & Jacob, 2009; Sasseville, 2004). Farmers, brewery workers, workers making binders for paints and glues, newsprint workers, woodworkers, steel foundry molders, lithoprinters, and funeral workers are also more likely to have ACD secondary to formaldehyde (Rietschel & Fowler, 2008).

A formaldehyde allergy can present in a variety of manners. A machinist or nurse may present with hand dermatitis, a woman with eyelid dermatitis from a new cosmetic product, or a man with axillae dermatitis from deodorant. Anaphylaxis and urticaria have been seen in patients receiving a formaldehyde-containing root-canal disinfectant (Frosch, Menne, & Lepoitteven, 2006). Shampoo can cause dermatitis at the hairline, eyelids, and ears (Sasseville, 2004). Most formaldehyde-sensitive patients can tolerate a shampoo with formaldehyde because it is rinsed off the scalp quickly. However, hairdressers can develop hand dermatitis due to frequent exposure to shampoo (Frosch et al., 2006).

Sources of formaldehyde (Maier et al., 2009; Marks et al., 2002; Rietschel & Fowler, 2008; Sasseville, 2004).

  • Shampoos, liquid soaps, cosmetics, nail polish, antiperspirants, and deodorants.

  • Photographic developers, papers, and solutions.

  • Tissue fixative, preservative for laboratory specimens, and embalming fluids.

  • Topical medications, renal dialysis equipment, dairy equipment, dental preparations, and orthopedic casts.

  • Dishwashing detergents, window and carpet cleaners, disinfectants, cleaners, furniture polishes, air fresheners, dry-cleaning spotting agents, and laundry detergents.

  • Plastic bags, foam rubber, and carpets.

  • Paper products: cardboard, newspapers, paper towels, paper tissues, magazines, hardcover and paperback books, glossy table paper, paper plates, paper cups, and wrapping paper. (Formaldehyde can give water-resistance and grease-resistance qualities to these products.)

  • Fabrics: Formaldehyde finishing solutions provide wrinkle-resistant quality to permanent press clothing, bedding, and drapery.

  • Metalworking fluids, cutting fluids, coolants, antifreeze materials, corrosion inhibitors, and flame retardants.

  • Adhesives, waterproof glue, water-based paints, paint remover, printing inks, lacquers, polishes (for cars, shoes, cements, and floors), and plastics (coating of cosmetic plastic containers).

  • Wood composites (including plywood and particle board), asphalt shingles, bonded leather, fertilizers, insulation, flooring materials, and leather tanning agents.

  • Rubber preservatives and antioxidants, and synthetic rubber production (may be released from polyvinyl chloride, nitrile, and latex rubber gloves).

  • Aspartame and gluten flour.

Overall, the frequency of formaldehyde allergies is decreasing due to the replacement of formaldehyde with alternative preservatives. Furthermore, it is used in more rinse-off products instead of leave-on products (Frosch et al., 2006). Aalto-Korte and colleagues (2008) found that 79% of patients with formaldehyde sensitivity were also allergic to at least one formaldehyde-releasing preservative.