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A positive cobalt spot test falsely indicating an occupational allergic contact dermatitis caused by cobalt
Author(s) -
Bruze Magnus,
Hamada Haneen,
Dahlin Jakob,
Dunér Kari,
Persson Lena
Publication year - 2013
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 - 10.1111/cod.12058
Subject(s) - cobalt , allergic contact dermatitis , contact dermatitis , dermatology , allergy , medicine , occupational exposure , patch test , chemistry , immunology , organic chemistry , medical emergency
Summary Background For investigation of chemical exposure in allergic individuals, spot tests are invaluable. A reagent may react with a specific compound to give a specific typical colour, and thus indicate the presence of the specific substance. Spot tests can give both false‐negative and false‐positive reactions. To confirm the presence of the substance and quantify it, more sophisticated methods are required. On the basis of a positive cobalt spot test result, a woman was initially diagnosed with an occupational allergic contact dermatitis caused by cobalt. Objectives To investigate cobalt release from three different metal weaves to which our patient was occupationally exposed. Methods The cobalt gel test and atomic absorption spectroscopy ( AAS ) were used to investigate the metal weaves. Two types of extract based on artificial sweat and nitric acid, respectively, were investigated with AAS . Results No cobalt release was demonstrated with AAS . Conclusions When a diagnosis of allergic contact dermatitis caused by a sensitizer based on a positive spot test result will have far‐reaching consequences, such as change of work, retraining, and claim on and payment of worker's compensation, conformational analysis must be performed.