Liquid synthetic detergents may be better cleansers for patients with atopic dermatitis

Key takeaways:

• All soaps had an undesirable pH (alkaline), whereas 84.9% of liquid synthetic detergents had an acidic pH.
• Only 12.8% of marketed skin cleansers disclosed pH.

WASHINGTON — Patients with atopic dermatitis may have better outcomes when using liquid synthetic detergents, according to a poster presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting.

“Shopping for skin cleanser products for atopic dermatitis can be dizzying with so many options available and different claims made on the labels,” Adil Khan, MD, allergy and immunology fellow at LSU Health Shreveport and the primary study author, said in an AAAAI press release. “Manufacturers that choose to disclose a products’ pH on the label can help narrow the choices. In particular, liquid synthetic cleansers most closely mimic normal skin pH.”

According to Khan’s research, healthy skin tends to be more acidic, whereas the skin of patients with AD is more alkaline, which contributes to the skin-barrier dysfunction characteristic of AD. As a result, patients with AD need to use soaps that are more acidic in nature.

To assess the pH components of commercially available skin cleansers, Khan and colleagues tested 240 products, 37 of which were soaps (32 bars, 5 liquids) and 213 of which were synthetic detergents, or syndets (14 bars, 199 liquids).

Results showed that while all soaps were alkaline with a pH range of 9.21 to 10.83, a majority of the syndets were acidic. Among the syndet bars, 42.9% had a neutral pH and 57.1% had an alkaline pH. However, among the liquid syndets, 84.9% had an acidic pH that ranged from 3.59 to 6.64, 11.1% had a neutral pH and only 4% had an alkaline pH of 7.4 to 8.56.

According to the press release, these findings suggest that patients with AD may find better results with liquid syndets vs. other skin care options.

Additionally, when it came to packaging, the pH was disclosed on none of the soaps and only 32 (15%) of the syndets. Of the syndets that did disclose the pH, nine were bars that were labeled “balanced,” with six of them testing as neutral and three as alkaline. Among the remaining 23 syndets, 20 were labeled as “balanced,” with two measuring as neutral and 18 measuring as acidic.

Overall, only 12.8% of marketed skin cleansers disclosed pH.

“Manufacturers should include the pH on labels so that clinicians can advise AD patients appropriately,” the authors wrote on the poster.

References:

• Khan A, et al. J Allergy Clin Immunol. 2024;doi:10.1016/j.jaci.2023.11.233.
• PH labelling of skin cleansers can lead to better options for people with atopic dermatitis. https://www.aaaai.org/about/news/news/2024/cleansers. Published Feb. 5, 2024. Accessed Feb. 27, 2024.