• Jasper L Selder and Jan Veenstra.
• Sint Lucas Andreas Ziekenhuis, afd. Interne geneeskunde, Amsterdam, the Netherlands. j.selder@slaz.nl
• Ned Tijdschr Geneeskd. 2013 Jan 1;157(29):A6206.

BackgroundThe use of creams is considered to be generally safe. However, systemic side effects can occur.Case DescriptionA 22-year-old woman came to the emergency department with dyspnea, confusion and 'blue' skin after laser treatment of the upper legs for excessive hair. She had used three tubes of a eutectic mixture of local anaesthetics (EMLA) cream containing lidocaine/prilocaine for analgesia. Her oxygen saturation was 87%, measured with pulse oximetry. Blood gas analysis showed a concentration of oxy-Hb of 79% and a met-Hb of 19%. Our working diagnosis was methaemoglobinaemia as a result of using excessive amounts of EMLA cream. Because the met-Hb concentration decreased spontaneously and the oxy-Hb concentration consequently normalised, we did not administer methylene blue. The patient was discharged symptom-free after several hours of observation.ConclusionAn overdose of EMLA cream, whether or not in combination with laser-induced skin damage, can produce a high systemic o-toluidine concentration. This can lead to methaemoglobinaemia. In such cases, the pulse oximeter is not reliable for measuring the oxygen saturation; therefore, blood gas analysis is necessary for making a diagnosis.

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