ABSTRACT
Background: Parthenium hysterophorus is the leading cause of phytogenic allergic contact dermatitis in India. The Indian Standard Series currently supplied by Systopic Laboratories Ltd and manufactured by Chemotechnique Diagnostics® contains parthenolide as the only allergen representing plant allergens. Aim: The study was conducted to assess the performance of the Chemotechnique plant series (PL-1000), consisting of 14 allergens, in patients with clinically suspected occupational contact dermatitis to plant allergens. Methods: Ninety patients were patch tested with the Chemotechnique plant series from 2011 to 2013. Demographic details, clinical diagnosis and patch test results were recorded in the contact dermatitis clinic proforma. Results: Of 90 patients, 24 (26.7%) showed positive reactions to one or more allergens in the plant series. Positive patch tests were elicited most commonly by sesquiterpene lactone mix in 19 (78.6%) patients, followed by parthenolide in 14 (57.1%), Achillea millefolium in 10 (42.9%) and others in decreasing order. Conclusion: The plant allergen series prepared by Chemotechnique Diagnostics® is possibly not optimal for diagnosing suspected allergic contact dermatitis to plants in north Indians. Sesquiterpene lactone mix should replace parthenolide as the plant allergen in the Indian Standard Series until relevant native plant extracts are commercially available for patch testing.