Sulfates are much maligned and while some are harsh, quite a few like SLS (Soduim Lauryl Sulfate/Sodium Dodecyl Sulfate) and SLES (Sodium Laureth Sulfate/Sodium Lauryl Ether Sulfate) are not published allergens. While some irritant (not allergic) reactions have been reported with SLS, there are far fewer with SLES and, in both cases, irritations seem to be directly related to their concentration in the formulation. On the other hand, several of the replacements used to make a product “sulfate-free” are allergens — the most common being”amido-amine” surfactants like CocAMIDE-Dea, CocAMIDOpropyl-Betaine, and CocAMIDOpropyl Hydroxysultaine. It’s not the coconut derivatives that are allergenic but the “amine” chemicals used to process them — which is why OleAMIDOpropyl Dimethylamine is also an allergen.

While cocamide-dea and cocamidopropyl betaine start out from the coconut, the allergenicity is not due to the coconut oil itself. It is the “amido-amine” chemicals — used in their processing — that are the allergens, not the coconut oil, meat, water, or other materials. Amido-amines are formed when diamines react with fatty acids derived from any oil — the long-chain fatty acids of soy oil or the medium-chain fatty acids of coconut oil — in the process of making surfactants. The fatty acids themselves are rarely, if ever, allergenic.
These chemicals are used to form bubbles in cleansers. Ironically, these top contact allergens are common in shampoos marketed as safer because they are “sulfate-free” shampoos — yet they are top contact allergens while sulfates are not.

For more:

• On the prevalence of skin allergies, see Skin Allergies Are More Common Than Ever.
• For the difference between irritant and allergic reactions, see It’s Complicated: Allergic Versus Irritant Reaction.
• For the difference between food, skin, and other types of reactions: see Skin & Food Allergies Are Not The Same Thing.
• To learn about the VH-Rating System and hypoallergenicity: What Is The Validated Hypoallergenic Rating System?

Main References: 

Regularly published reports on the most common allergens by the North American Contact Dermatitis Group and European Surveillance System on Contact Allergies (based on over 28,000 patch test results, combined), plus other studies. Remember, we are all individuals — just because an ingredient is not on the most common allergen lists does not mean you cannot be sensitive to it, or that it will not become an allergen. These references, being based on so many patch test results, are a good basis but it is always best to get a patch test yourself.

1. Warshaw, E.M., Maibach, H.I., Taylor, J.S., et al. North American contact dermatitis group patch test results: 2011-2012. Dermatitis. 2015; 26: 49-59.
2. W Uter et al. The European Baseline Series in 10 European Countries, 2005/2006–Results of the European Surveillance System on Contact Allergies (ESSCA). Contact Dermatitis 61 (1), 31-38.7 2009.
3. Wetter, DA et al. Results of patch testing to personal care product allergens in a standard series and a supplemental cosmetic series: An analysis of 945 patients from the Mayo Clinic Contact Dermatitis Group, 2000-2007. J Am Acad Dermatol. 2010 Nov;63(5):789-98.
4. Verallo-Rowell VM. The validated hypoallergenic cosmetics rating system: its 30-year evolution and effect on the prevalence of cosmetic reactions. Dermatitis 2011 Apr; 22(2):80-97.
5. Ruby Pawankar et al. World Health Organization. White Book on Allergy 2011-2012 Executive Summary.
6. Misery L et al. Sensitive skin in the American population: prevalence, clinical data, and role of the dermatologist. Int J Dermatol. 2011 Aug;50(8):961-7.
7. Warshaw EM1, Maibach HI, Taylor JS, Sasseville D, DeKoven JG, Zirwas MJ, Fransway AF, Mathias CG, Zug KA, DeLeo VA, Fowler JF Jr, Marks JG, Pratt MD, Storrs FJ, Belsito DV. North American contact dermatitis group patch test results: 2011-2012.Dermatitis. 2015 Jan-Feb;26(1):49-59.
8. Warshaw, E et al. Allergic patch test reactions associated with cosmetics: Retrospective analysis of cross-sectional data from the North American Contact Dermatitis Group, 2001-2004. J AmAcadDermatol 2009;60:23-38. 
9. Foliaki S et al. Antibiotic use in infancy and symptoms of asthma, rhinoconjunctivitis, and eczema in children 6 and 7 years old: International Study of Asthma and Allergies in Childhood Phase III. J Allergy Clin Immunol. 2009 Nov;124(5):982-9.
10. Kei EF et al. Role of the gut microbiota in defining human health. Expert Rev Anti Infect Ther. 2010 Apr; 8(4): 435–454.
11. Thavagnanam S et al. A meta-analysis of the association between Caesarean section and childhood asthma. Clin Exp Allergy. 2008;38(4):629–633.
12. Marks JG, Belsito DV, DeLeo VA, et al. North American Contact Dermatitis Group patch-test results, 1998 to 2000. Am J Contact Dermat. 2003;14(2):59-62.
13. Warshaw EM, Belsito DV, Taylor JS, et al. North American Contact Dermatitis Group patch test results: 2009 to 2010. Dermatitis. 2013;24(2):50-99.
14. Verallo-Rowell V. M, Katalbas S.S. & Pangasinan J. P. Natural (Mineral, Vegetable, Coconut, Essential) Oils and Contact Dermatitis. Curr Allergy Asthma Rep 16,51 (2016) . https://doi.org/10.1007/s11882-016-0630-9.
15. de Groot AC. Monographs in Contact Allergy, Volume II – Fragrances and Essential Oils. Boca Raton, FL: CRC Press Taylor & Francis Group; 2019.
16. De Groot AC. Monographs in Contact Allergy Volume I. Non-Fragrance Allergens in Cosmetics (Part I and Part 2). Boca Raton, Fl, USA: CRC Press Taylor and Francis Group, 2018.
Want more great information on contact dermatitis? Check out the American Contact Dermatitis Society, Dermnet New Zealand, and your country’s contact dermatitis association.

Laura is our “dew”-good CEO at VMV Hypoallergenics and eldest daughter of VMV’s founding dermatologist-dermatopathologist. She has two children, Madison and Gavin, and works at VMV with her sister CC and husband Juan Pablo (Madison and Gavin frequently volunteer their “usage testing” services). In addition to saving the world’s skin, Laura is passionate about health, inclusion, cultural theory, human rights, happiness, and spreading (like a VMV cream!) goodness!