By Henry Ehrlich
At our annual New York Allergy and Asthma Society Teaching day, we heard NYU-Langone dermatologist David E. Cohen, MD, MPH update us on the exciting new developments in treating atopic dermatitis (AD). He said that AD is years behind psoriasis, which anyone who watches TV knows because of the many commercials for Humira and Stelara and none for Dupixent. The problem is that psoriasis is always the same disease, but atopic dermatitis is always changing because of the different seasons and other variables. It’s hard to hit a moving target. But don’t worry, its time will come.
The fun part of the talk was not about AD, it was about Dr. Cohen’s real passion, contact dermatitis. He said that he had gained some insight recently into the proliferation of contact dermatitis when showering at the home of his grown daughter and seeing half a dozen bottles of shampoos, conditioners, rinses, body washes, and moisturizers, all of which contain a witch’s brew of natural and unnatural ingredients. He reminded the group that the American Contact Dermatitis Society each year chooses an “allergen of the year” (which we also covered here), and gently mocked the allergists for not coming up with that idea first.
Previous winners included (thanks to the Society’s publication The Dermatologist):
Benzophenone (2014) “a group of aromatic ketones that can absorb UVA and UVB rays…They were initially used as preservatives to prevent photodegradation and extend the shelf life of items such as paints and varnishes. In the 1950s, however, benzophenones were added to sunscreens as chemical UV absorbers.
Today, benzophenones can be found in sunscreens, perfumes, soaps, nail polish, hair sprays and dyes, body washes, body moisturizers, shampoos, paints, pesticides, textiles, inks, adhesives and plastic lens filters used in color photography.
The previous year, honors went to Methylisothiazolinone, which has a colorful history.
“In the 1940s, the Chicago-based company Chemtoy revolutionized the toy industry by selling bubble solutions, and in the 1960s, bubbles became a sign of peace during the ‘hippie movement’.” Superballs were another hot item. “Methylisothiazolinones (MIs) are biocidal preservatives added to bubble solutions, bubble baths, soaps and cosmetic products. The biocidal activity comes from their ability to interact with microorganisms and oxidize accessible cellular thiols. The chemical structure (2-methyl-4-isothiazolin-3-one) makes them highly compatible with surfactants and emulsifiers. In addition, MIs can maintain their biocidal activity over a wide pH range, making them favorable for use as preservatives in surfactants.”
The winning allergens are sometimes not so exotic. Nickel allergy (2008) is well-known. So is “Fragrance (2007) Corticosteroids (2005) is another.
The histories of these things range from ancient to modern. Cocamidopropyl Betaine (2004)
“The earliest written accounts of soapmaking practice date back to ancient Babylon, around 2800 BC. Ancient Egyptian historical documentation in the ‘Ebers Papyrus’ describes the combination of animal and plant fats with alkaline salts to create soap for use in bathing. The first synthetic detergent was developed by the Germans during WWI to compensate for the shortage of fats.”
The 2017 winner Alkyl Glucoside has been used with at least some consideration to environmental considerations. “These surfactants have been available for more than forty years; however, they have been been used more recently because of their “eco-friendly” properties. These nonionic surfactants are plant derived with complete biodegradability. They are mainly from palm or coconut oil. Alkyl glucosides are used in various leave-on and rinse-off cosmetics and are considered of low irritancy and allergenicity.” But sooner or later, the ever-adaptive immune system finds a way to react. “Decyl glucoside was found to be a “hidden” allergen in the sunscreen ingredient Tinosorb M. Members of the North American Contact Dermatitis Group have seen a steady increase of the rate of sensitization to decyl glucoside.”
Now please excuse me while I moisturize.