CD03 Contact sensitization to shellac: a possible marker of fragrance allergy

Abstract Shellac, the purified resin produced from female lac bug (Kerria lacca), has its application within a wide range of industries, including healthcare, food, wood treatments and cosmetics. Shellac 20% alcohol is included in British Society for Cutaneous Allergy/European Contact Dermatitis extended facial series based on frequency reactions exceeding 0.3% threshold. However, source primary sensitization remains difficult to characterize through patch testing as relevance not always clear test preparation an irritant potential. We present 28 patients 2013 2022 with positive or shellac, elucidate reaction pattern our outpatient population. Cases confirmed shellac positivity (‘+’ higher) using (Chemotechnique MB Diagnostics, Vellinge, Sweden) days 2 4 cosmetic were retrieved between total 5458 people tested. Data collected records degree positivity, irritancy, relevance, coexisting allergens, anatomical site previous history atopy. processed Microsoft Excel. report 21 reactions, 14 (67%) which weak. Eleven (52%) deemed current seven (33%) doubtful one (5%) past crossreaction fragrance. Seven (25%) had documented shellac. Nickel colophony most common allergens shellac-positive (positive five four cases, respectively). Nine (43%) cases fragrance markers (which more geraniol, citral, Evernia furfuracea, turpentine, propolis, colophony, abitol, isoeugenol, cinnamyl alcohol, Jasminum officinale, jasmine absolute, majantole benzaldehyde), indicating higher prevalence than existing rates studies general Fourteen face disease, 16 (76%) personal Our results indicate significant association allergy, suggesting role marker allergy due cross-reaction. When comparing proportion this was US population-based reports (five vs. 64 cohort 612 cases) but significantly lower recent German study (90 76 2167), all instances preparation.