Two Cases of Allergic Contact Dermatitis Caused by Coco Betaine in Clobetasol Propionate Shampoo

Sep 28, 2026

Uploaded by Levi

Report two cases of allergic contact dermatitis attributed to the amphoteric surfactant coco betaine, an additive in clobetasol propionate shampoo, despite the formulation’s generally low allergenic potential. Both Japanese male patients had long-standing severe atopic dermatitis and were treated with oral cyclosporine. Patch testing showed clearly positive reactions to coco betaine 1% aqueous solution in both cases, while reactions to clobetasol propionate shampoo and related surfactants varied between patients. The study emphasizes that refractory scalp dermatitis may be driven by topical medication ingredients rather than the steroid “active.”

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Introduction

Case Report

Case 1

Case 2

Wiley Case Reports in Dermatological Medicine Volume 2026, Article ID 9953943, 5 pages [https://doi.org/10.1155/crdm/9953943](https://doi.org/10.1155/crdm/9953943) Case Report Two Cases of Allergic Contact Dermatitis Caused by Coco Betaine in Clobetasol Propionate Shampoo Shigeruko Iijima , 1 Kayo Murayama, 1 Noriko Takayama, 1 Mariko Sugiyama,2 and Kayoko Matsunaga 2,3,4 1 Division of Dermatology, Hanamizuki Clinic, Ushiku, Ibaraki, Japan 2 General Incorporated Association SSCI-Net, Nagoya, Aichi, Japan 3 Fujita Health University, Toyoake, Aichi, Japan 4 Department of Dermatology and Allergy, Kariya Orthopedic Hospital, Kariya, Aichi, Japan Correspondence should be addressed to Shigeruko Iijima; [imacintosh@poppy.ocn.ne.jp](imacintosh@poppy.ocn.ne.jp) Received 9 October 2024; Revised 19 November 2025; Accepted 20 November 2025 Academic Editor: Semonti Nandi Copyright © 2026 Shigeruko Iijima et al. Case Reports in Dermatological Medicine published by John Wiley & Sons Ltd. Tis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. We present two cases of allergic contact dermatitis caused by the amphoteric surfactant coco betaine, a constituent of clobetasol propionate (CP) shampoo, despite the low allergenic potential of CP shampoo formulations. Te patients were Japanese males, aged 49 and 52 years, with severe atopic dermatitis, who had been treated with oral cyclosporine for several years. Patch testing revealed that only coco betaine 1% aq. showed a clearly positive reaction in both cases, whereas the patch test results of CP shampoo, cocamidopropyl betaine, and lauramidopropyl betaine were positive in one case and doubtful in the other. In cases of recalcitrant scalp dermatitis, it is necessary to consider the possibility that it is being caused by the topical medication used to treat it, and that the “active” ingredient may not be the culprit. Keywords: allergic contact dermatitis; amphoteric surfactant; CAS RN 61789-40-0; CAS RN 68424-94-2; clobetasol propionate shampoo; cocamidopropyl betaine; coco betaine 1. Introduction Clobetasol propionate (CP) shampoo (Comclo®; Maruho Co., Ltd., Osaka, Japan) contains a super high–potency topical corticosteroid and several surfactants. In Japan, CP shampoo was frst approved as a treatment for scalp psoriasis in July 2017, and it was later approved as a treatment for scalp eczema in February 2021 . Recently, Ramani et al. [1] reported that CP shampoo formulations contain fewer potential allergens than other CP-containing products. In this report, we present two cases of allergic contact dermatitis caused by the amphoteric surfactant coco betaine, one of the additives of CP shampoo. Our report is unique because only a few cases of allergic contact dermatitis triggered by additives, especially surfactants such as coco betaine, have been reported in the literature [2, 3], and patch tests of cocamidopropyl betaine (CAPB)/lauramidopropyl betaine (LAPB) were also performed in our cases, as they share some structural similarities with coco betaine. 2. Case Report 2.1. Case 1. A 49-year-old Japanese male with scalp dermatitis was using betamethasone butyrate propionate (Antebate®) lotion. After a positive patch test of his previous shampoo, it was replaced with a less irritating one, resulting in his scalp being in good condition for 1.5 years. However, signifcant dandruf reappeared, and CP shampoo was prescribed. Although an initial improvement was observed after 2 weeks, the therapeutic efect diminished after 1 month (Figure 1(a)) . 2 Case Reports in Dermatological Medicine (a) (b) (c) CP shampoo 1% aq. Coco betaine 1% aq. CAPB 1% aq. LAPB 1% aq. Figure 1: Clinical (a, b) and patch test fndings obtained on D3 (c) in Case 1 . Clinical fndings of Case 1 before (a) and after (b) the use of CP sha

FAQs

What ingredient is identified as the main cause in these two cases?

The amphoteric surfactant coco betaine is identified as the causative agent, supported by positive patch test results to coco betaine 1% aqueous solution in both cases.

How do patch test results differ between clobetasol propionate shampoo and coco betaine?

In both cases, coco betaine 1% aqueous solution produced clearly positive reactions; however, clobetasol propionate shampoo showed positive in one case and doubtful in the other, indicating inconsistent reactivity.

Why is coco betaine suspected even though clobetasol propionate shampoo is considered low allergenic?

The cases show dermatitis recalcitrant to changes in treatment and demonstrate that the additive coco betaine can trigger allergic contact dermatitis, suggesting the “active” ingredient may not be the culprit.

Sep 28, 2026

Uploaded by Levi