CD07 Benzyl alcohol as a clinically relevant excipient allergen: a case series from a tertiary cutaneous allergy centre

Abstract

Allergic contact dermatitis (ACD) to topical medicaments may complicate atopic dermatitis and should be considered when eczema persists or worsens despite appropriate therapy. Benzyl alcohol is a widely used excipient with preservative and solvent properties and is present in numerous pharmaceutical formulations, including topical medicaments. Crossreactivity between benzyl alcohol and balsam of Peru (Myroxylon pereirae) has been reported, likely reflecting shared aromatic constituents. At our tertiary cutaneous allergy centre, 7008 patients were patch tested to the Chemotechnique Diagnostics cosmetic series containing benzyl alcohol (1% in petrolatum), of whom 38 demonstrated positive reactions. We present a case series of four of these patients in whom benzyl alcohol was identified as an allergen of current clinical relevance within prescribed topical medicaments. Two of the four patients were additionally positive to balsam of Peru. The first case involved a 13-year-old girl with atopic dermatitis and a 7-year history of persistent facial dermatitis, partially responsive to pimecrolimus. Patch testing demonstrated positive reactions to benzyl alcohol and to her pimecrolimus cream, which contained benzyl alcohol as an excipient. The second case involved a 41-year-old woman with atopy who presented with hand dermatitis. Patch testing demonstrated sensitivity to benzyl alcohol, which was identified in her own prescribed emollient. The third patient also had exposure through her prescribed emollient containing benzyl alcohol. She was a 39-year-old woman with widespread facial and truncal dermatitis, who patch tested positive to benzyl alcohol and balsam of Peru. The fourth case is of a 65-year-old woman with recurrent eyelid dermatitis, in whom patch testing demonstrated positivity to benzyl alcohol, which was an excipient in her topical tacrolimus ointment, and to balsam of Peru. Benzyl alcohol is an uncommon but recognized excipient sensitizer present in a wide range of topical medicaments. This case series highlights the importance of patch testing with patients’ own products, and aims to raises prescriber awareness of excipient allergens as a possible cause of treatment resistance or failure.