Patch Testing to Lauryldimethylamine Oxide: Clinical Relevance and Cross-Reactivity with Cocamidopropyl...

Lauryldimethylamine oxide (LDAO), or lauramine oxide, is an amine-oxide-based surfactant to which allergic contact dermatitis (ACD) has been reported. We present our experience of routinely patch testing LDAO between 2024 and 2026, characterizing positivity rate, clinical relevance, and concomitant reactions with the cocamidopropyl betaine (CAPB) family.

Seven hundred sixty-six patients were tested to LDAO at our tertiary referral center. Data collection included reaction strength, clinical relevance, primary site of dermatitis, exposure sources, and concomitant reactions.

Twenty-nine patients (3.79%) reacted to LDAO at their final reading, and LDAO had definite or probable clinical relevance in 8 of these patients (27.6%). Primary sites of dermatitis included the face (4), hands (2), eyelids (1), and scalp (1). LDAO was declared in dishwashing soaps (6) and hand soaps (2) in clinically relevant cases. Cross-reactivity between LDAO and the CAPB family was clinically and statistically significant.

Our results suggest clinical cross-reactivity between amine oxides and the CAPB family. LDAO-allergic patients should avoid amine oxides and CAPB-related compounds. We recommend LDAO be more routinely tested, as it may help identify amine oxide- or CAPB-related ACD that would otherwise be missed.