Symptoms of immediate chlorhexidine hypersensitivity in patients with a positive prick test.

There are numerous reports of anaphylaxis from chlorhexidine in surgical operations and other medical procedures, usually due to its application to wounds or mucous membranes. We wanted to analyse the clinical data of patients with a positive chlorhexidine prick test and perform some additional testing. We studied the case records of the patients with a positive chlorhexidine prick test and performed an open application test and tests for specific IgE. We found 33 patients with a positive prick test. 10 of them had had severe symptoms from chlorhexidine, and 11 had had only mild local symptoms. The size of the prick test reaction was mainly in line with the strength of the severest symptoms. Small 3- to 4-mm reactions were usually without obvious clinical relevance. Specific IgE could be demonstrated in 6 patients out of 14 tested by the ImmunoCAP method. Besides severe attacks, patients with a positive prick test often have milder local symptoms, such as exacerbation of dermatitis. Local symptoms from chlorhexidine-containing products may precede severe attacks. We recommend a prick test to be performed routinely when symptoms during medical interventional procedures, e.g. local and general anaesthesia, are investigated.