Soaps and cleansers for atopic eczema, friends or foes? What every South African paediatrician should know about their pH

Abstract

Background. Knowledge of the pH level of soaps and cleansers used by patients with atopic eczema and sensitive skin is crucial, as high-alkalinity products are irritants and impair the normal skin barrier, so interfering with the adequate control of atopic eczema.

Objectives. The aim of this study was to assess the pH of various bar soaps and cleansers that are usually recommended and used by patients with atopic diseases and dry, sensitive skin in South Africa.

Methods. Forty-nine commercial soap bars and cleansers were randomly selected for pH analysis. The samples were prepared as 8% emulsions in tap water. Nine undiluted liquid facial cleansers were also evaluated. Deionised water was used as a negative control. The pH of each emulsion or liquid cleanser was recorded in duplicate using a Metrohm pH meter model 827 (Metrohm, Herisau, Switzerland).

Results. Of the 49 samples analysed, 34 (69.4%) were alkaline with a pH ranging from 9.3 - 10.7. Two samples (4.1%) were within the acceptable range of (5.4 - 5.9), and 2 samples (4.1%) had pH levels of below 5. In total, 5 samples (10.2 %) had a pH of 4 - 6.

Conclusion. The majority of soaps and cleansers analysed in this study were alkaline, with only 2 falling in the acceptable pH range of 5.4 - 5.9 and 5 within the pH range of 4 - 6, thus raising concerns regarding the optimal management of atopic eczema patients.