Clinical relevance of positive patch test reactions to lanolin: A ROAT study

BACKGROUND: Lanolin is often included when patch testing for common contact allergens. The clinical relevance of a positive patch test reaction to lanolin markers is, however, still a subject for debate. OBJECTIVES: To evaluate Amerchol L101 as a marker of lanolin allergy and investigate the clinical impact of lanolin‐containing moisturizers on healthy and damaged skin using the repeated open application test (ROAT). METHODS: Twelve test subjects and 14 controls were patch tested with Amerchol L 101 and additional lanolin markers. Subsequently, a blinded ROAT was performed on the arms of the study participants for 4 weeks. Each participant applied a lanolin‐free cream base and two different lanolin‐containing test creams twice daily on one arm with intact skin and on the other arm with irritant dermatitis, induced by sodium lauryl sulfate (SLS). RESULTS: Eleven test subjects (92%) had positive patch test reactions to Amerchol L 101 when retested and one test subject (8%) had a doubtful reaction. None of the study participants had any skin reactions to the ROAT on intact skin and all participants healed during the ROAT on damaged skin. CONCLUSIONS: Lanolin‐containing emollients do not cause or worsen existing dermatitis when performing ROAT in volunteers patch test positive to Amerchol L101.