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Patch testing with neomycin sulfate
Author(s) -
Bjarnason Bolli,
Flosadóttir Ellen
Publication year - 2000
Publication title -
contact dermatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 96
eISSN - 1600-0536
pISSN - 0105-1873
DOI - 10.1034/j.1600-0536.2000.043005295.x
Subject(s) - neomycin , polyester , patch test , chromatography , patch testing , medicine , dermatology , surgery , chemistry , contact dermatitis , immunology , allergy , antibiotics , biochemistry , organic chemistry
The recommended patch test concentration of neomycin sulfate is 20% in petrolatum applied occluded for 48 h (2 days [D]). In the current study, the efficiency of such a test is compared to results with other techniques using lower allergen dose than obtained by approximately 20 μl of the 20% substance. Efficiency of petrolatum and demineralized water as vehicles are compared. 16 neomycin‐sulfate positive subjects were retested with serial doses ranging from 0.4 to 0.0085 mg/cm 2 neomycin sulfate in cellulose printed on polyester squares and applied by both tapes and plastic foils. Additionally, tests were performed with the 20% petrolatum substance in Finn Chambers ® . Tests containing the 20% substance in petrolatum and in water were applied directly with transparent foils. Readings ranged from 3 to 264 h (11D) following applications. Results show that foil applications of a polyester square dose, that is 7% of the dose obtained with the 20% substance, distinguished between perfusion of subjects who were visually positive and not with any test in the study. With the same test technique and visual assessments, 2 subjects were false‐negative but developed doubtful test responses with the Finn Chambers ® .