Cocamidopropyl betaine contaminants
Patients may develop allergic contact dermatitis after using shampoos and bath gels containing cocamidopropyl betaine, a surfactant.
In fact, they are actually reacting to a contaminant or impurity generated in the manufacturing process, either 3-dimethylaminopropylamine or amidoamine, according to Dr. Marks.
"So if you have pure cocamidopropyl betaine, there will be no allergy," he noted. But if you test for "cocamidopropyl betaine, and what you are patch testing with is from, say, Chemotechnique or Allergeaze, it’s going to have presumably the contaminants or the impurities in it, 3-dimethylaminopropylamine and amidoamine."
Treatment entails careful reading of labels on personal care products and avoidance of those containing cocamidopropyl betaine.
Acrylates
Don’t rule out acrylates – either acrylic or methacrylic acid – monomers that are polymerized with heat or light to form solid plastics that can cause reactions.
"The monomers are both irritants and allergens, so you need the right concentration to patch test to," Dr. Marks noted. "They are found in all sorts of things – adhesives, inks, artificial nails, dental resins, bone cement, and plastics."
Presentations may vary widely, including, for example, finger dermatitis in patients who have sculptured nails, and gum stomatitis in patients who have undergone procedures involving dental resin, said Dr. Marks.
"If you have workers or patients who have exposure to acrylates, you need more extensive screening," Dr. Marks advised, noting that his acrylate patch test series contains six compounds.
"No one is a screen for all of them," he commented. "Some [experts] feel that ethyl acrylate is the best screen; certainly, for sculptured nails it’s good." Others in his series include methyl methacrylate (found in bone cement) and ethyl cyanoacrylate (found in Super Glue adhesive).
Glyceryl thioglycolate
Allergy to glyceryl thioglycolate, found in acid permanent waves, can manifest as hand dermatitis in hairdressers and as dermatitis of the face, neck, and ears in their clients.
"If you see hairdressers [in your practice], you should consider strongly having this antigen as part of your [patch test] armamentarium," Dr. Marks recommended.
Alkaline perms, by contrast, do not contain glyceryl thioglycolate and thus provide a simple solution. "You can cure that hairdresser, and she or he can continue to do perms just by switching from an acid to an alkaline perm," he explained.
Dr. Marks said he had no relevant financial disclosures.