a medication error can be defined as  a failure in the treatment process that leads to , or has the potential to lead to , harm to the patient. the use of the term failure signifies that the process has fallen below an attainable standard . as per the us institute of medicine 's report ( 1999 )  to err is human , every year 7000 preventable adverse drug reactions in usa were due to medication errors . to the best of our knowledge , this is the first report on the adverse event of intradermal hypersensitivity testing with cloxacillin resulting in pain and skin necrosis as a result of medication error . we describe a case report of cloxacillin - induced skin necrosis which occurred following intradermal skin testing for screening of hypersensitivity response . intradermal skin testing for diagnosing hypersensitivity response to cloxacillin was done for three patients who were admitted in the surgery ward of a tertiary care hospital . this included a 12-year - old boy diagnosed with cryptorchidism and admitted for inguinal exploration , a 28-year - old male admitted for bilateral breast mass reduction , and a 52-year - old male who was admitted for inguinal mass exploration . the test dose was given in the forearm of each patient , one after the other , using the same diluted preparation of cloxacillin . the nurse who prepared the test dose solution had apparently mixed 500 mg of cloxacillin sodium in 2 ml of distilled water , and had used 0.1 ml of the solution for intradermal injection in each of the three patients . however , the institute protocol for intradermal skin testing was only 0.5 mg per test dose . all three patients complained of intense pain , itching and rash over the site of injection within 30 min of receiving the test dose intradermal . this was followed by darkening of skin over the injected area which progressed to necrosis within 6 to 12 h and was associated with persistent pain [ figures 1 and 2 ] . after 12 h of receiving the test dose , pain subsided spontaneously in all three patients . skin necrosis at the site of intradermal test dose skin necrosis at the site of intradermal test dose adverse drug reactions are one of the important causes for significant morbidity and mortality among patients . among various causes for adverse drug reactions , medication errors include administration of a drug which is inappropriate for the condition or at an inappropriate dose . a study by kopp et al . , on medication errors in intensive care patients showed that around 17% of medication errors resulted in adverse drug reactions which were preventable . further , 83% of medication error had the potential to cause adverse drug reactions . in a study by bates , approximately 28% of adverse drug events were due to medication errors which were preventable . further , studies had also shown that the most common cause of medication error ( 36% ) was due to overdose followed by selection of wrong drug and wrong route of drug administration . this article highlights the seriousness of the reaction which could potentially occur with cloxacillin due to medication error . since the drug was given at 50 times the dose recommended for intradermal testing as per the institute protocol , the patient faced a serious risk of developing serious adverse events such as anaphylaxis . there had been reports of patients developing anaphylaxis even with the low dose used for penicillin hypersensitivity intradermal skin test . many of the medication errors occurred due to oversight or negligence during the process of prescribing , dispensing , storage and administration of drug . in a hospital setup , this could occur due to oversight by the nursing staff responsible for administering the drug . some of the common reasons could be overtime working , under trained staff , unsupervised nursing interns , complicated and unclear protocols , interpersonal communication gap between health care professionals and also poor availability of ideal resources . in this report , the drug was diluted in a wrong way by an unsupervised nursing intern . there is an important role for pharmacovigilance centers that can contribute to the detection and prevention of medication errors and increasing the safety of patients . these centers must alert health care professionals about the importance of reporting medication errors through bulletins and journals .
medication error is one of the important causes of preventable adverse drug reactions . 
 it can occur in the form of administration of a wrong drug , in the wrong dose , to the wrong patient , in an unsuitable dosage form , for the wrong duration or by using an inappropriate route of administration . 
 intradermal skin testing for cloxacillin hypersensitivity is done at low doses to check for drug allergy . in this report , three patients were given 50 times higher dose of cloxacillin than recommended for skin testing , resulting in pain and necrosis at the site of injection . 
 the error occurred due to wrong dilution of the drug as done by a nursing intern . 
 some reasons for this could be overtime working , under trained staff , unsupervised nursing interns , complicated and unclear protocols , interpersonal communication gap between health care professionals and also poor availability of ideal resources . 
 pharmacovigilance centers must alert health care professionals about the significance of reporting medication errors through bulletins and journals .