Petechial Eruption After the Application of EMLA Cream

Abstract

The use of EMLA (eutectic mixture of local anesthetics) cream, especially in pediatrics and dermatology, has significantly reduced emotional and physical discomfort during typically uncomfortable procedures such as venipuncture, intravenous cannulation, lumbar puncture, curettage of molluscum contagiosum lesions, laser therapy of vascular birthmarks, skin biopsy, and cryosurgery of verrucae.EMLA cream is a mixture of lidocaine (25 mg/L) and prilocaine (25 mg/L), [an emulsifier], arlatone 289, [a thickener], carbopol 934, [sodium hydroxide] to adjust the pH to 9.4, and distilled water.1 For EMLA cream to act as an effective topical anesthetic, it must be applied to intact skin for at least 1 hour before the procedure and occluded with either Saran Wrap or Tegaderm.2 The duration of application of EMLA cream varies with the site of application and type of procedure performed.2 The amount of EMLA applied will depend on the surface area involved. Usually, 1 to 2 g of EMLA cream are applied per 10 cm2.Most patients tolerate the application of EMLA cream without adverse effects. The most common local effect is transient blanching of the skin,3 which is most often noted upon removal of the dressing and is caused by the active ingredients in EMLA cream.4 However, the mechanism of this effect is not clear. Erythema can also be observed after the application of EMLA cream.4 Villada et al4 found that erythema was noted most often 2 hours after application of EMLA cream. The erythema is usually asymptomatic and transient. Although the mechanism of the transient erythema is not understood, it seems to occur with greater frequency as the application time of EMLA cream increases.5There have been few reports of other cutaneous reactions including allergic contact dermatitis67 and urticaria.5Rarely, petechial or purpuric reactions can occur after the application of EMLA cream.181415 Herein, we report a case of a petechial eruption after the application of EMLA cream.A 16-month-old white girl presented to the Department of Pediatric Dermatology at the Mayo Clinic for treatment of several molluscum contagiosum papules. Her past medical history was significant for mild atopic dermatitis as an infant. She was not on any concurrent medications. On skin examination, involving the right chest, lateral torso, and upper arm were multiple, 1 mm to 10 mm, flesh-colored and erythematous, firm, waxy, variably umbilicated papules. There was no underlying or surrounding eczema.In preparation for curettage of the molluscum papules, fewer than 5 g of EMLA cream were applied by a nurse to the affected area on the torso and right upper arm and occluded with Saran Wrap and Tegaderm, respectively. One hour later, upon removal of the occlusive dressings, our patient was noted to have a brightly erythematous, variably blanching and nonblanching, petechial eruption surrounded by a subtle rim of pallor on the right chest and lateral torso (Fig1 and Fig2). Interestingly, the right upper arm was uninvolved despite the application of EMLA cream. The child was otherwise asymptomatic. Because of the petechial eruption, the molluscum papules on the torso were not treated, whereas those on the right upper arm were removed with a disposable curette.A skin biopsy and other laboratory studies were not obtained. The patient was prescribed a low potency topical steroid and was followed closely. The eruption cleared completely without sequelae after 2 weeks.The application of EMLA cream as analgesia before curettage of molluscum contagiosum lesions is common practice for dermatologists treating children. Studies have confirmed its effectiveness in reducing the discomfort associated with the procedure.89Furthermore, these same studies have demonstrated that EMLA cream can be used safely in children with minimal, transient vasoreactions, such as pallor and erythema. No significant systemic reactions have been noted in these studies. Studies have also been performed to evaluate plasma levels of lidocaine and prilocaine in children after the application of EMLA cream for removal of molluscum contagiosum lesions.1011 In these studies, plasma levels of lidocaine and prilocaine were significantly below toxic levels. However, rarely, prilocaine may cause methemoglobinemia as a result of two of its metabolites, 4-hydroxy-2-methylaniline and 2-methylaniline(o-toluidine).2 Children, but more so infants <3 months of age are at risk of developing increased levels of methemoglobin because of decreased activity of erythrocyte methemoglobin reductase, which is the enzyme responsible for converting methemoglobin to hemoglobin.1210-13Therefore, EMLA is contraindicated in infants <12 months, who are taking methemoglobin-inducing medications such as sulfonamides, acetaminophen, nitroglycerin, nitroprusside and phenytoin, or in anyone with a history of methemoglobinemia.2There have been a few published reports of petechial or purpuric reactions occurring in children after the application of EMLA cream181415 (Table). Rosdahl et al8 report the occurrence of petechiae in the groin or axilla 1 hour after application of <10 g of EMLA cream in three children, all of whom had atopic dermatitis.8 These children did not develop petechiae in other treated areas. de Waard-van der Spek et al1 describe purpura 30 minutes after the application of EMLA cream in 2 children, however, a history of atopic dermatitis in these children and the sites of application are not mentioned. Gourrier et al14 report their experience with EMLA cream in the neonatal unit. In 4 newborns, 3 of whom were <30 weeks gestation and 1 of whom was 31.5 weeks gestation, a purpuric eruption developed after 90 to 120 minutes at the site of application of EMLA cream.14 The amount applied was small, according to the authors, being less than one eighth to one sixth of a tube (the authors do not specify the amount of EMLA cream per tube). The purpura was noted immediately upon removal of the occlusive film and resolved spontaneously without sequelae.14 One of their patients had a concurrent thrombocytopenia, but this was not so for the other neonates. These authors observed a purpuric eruption in 57% of EMLA cream applications during the first 3 days of life in neonates of 30 weeks gestational age or younger, whereas a purpuric eruption followed the use of EMLA cream in only 3.3% of applications in neonates between 30 and 32 weeks of gestational age.14 Juhlin and Rollman15 report 1 adult with atopic dermatitis who developed purpura in the test area on the shoulder region after a 60-minute application.15 As with our patient, the petechiae and purpura in these cases resolved without sequelae after several days.11415The mechanism of this particular vascular reaction is not understood. However, Gourrier et al14 speculate that absorption of EMLA cream is accelerated in the skin of premature infants and may provoke local extravasation of blood that may be facilitated by transient capillary fragility. Therefore, it is their recommendation that EMLA cream not be used in premature infants <32 weeks gestation before the seventh day of life.14 Under special circumstances, one could use EMLA cream after the fourth day of life in a premature infant between 30 and 32 weeks gestation.14 Also, this vascular reaction appears to occur more commonly in patients with atopic dermatitis where the barrier function of the stratum corneum is diminished, perhaps resulting in greater and faster absorption of the EMLA cream, which then somehow causes extravasation of blood.Although not a frequent reaction after the application of EMLA cream, physicians need to be aware that patients can develop an asymptomatic purpuric eruption, which resolves without sequelae. Premature neonates and patients with atopic dermatitis appear to be at greater risk of developing this purpuric or petechial reaction. Whether future applications of EMLA cream are contraindicated in patients who have had a previous petechial or purpuric reaction is unclear. However, Gourrier et al14 note that 2 of their 4 patients who had developed a prior purpuric reaction, did not do so when accidentally rechallenged with EMLA cream a few weeks later. Thus far, our patient has not had any additional applications of EMLA cream.After submitting this manuscript, we witnessed another identical petechial eruption after the application of EMLA cream. Our patient was a 5-year-old white boy with several molluscum lesions on the torso, arms, left thigh, and inguinal region. He had no associated molluscum dermatitis and no known history of atopic dermatitis. In preparation for curettage of these lesions, his mother applied 5 g of EMLA cream occluded with Tegaderm to his left thigh. Approximately 2½ hours later, upon removal of the Tegaderm and EMLA cream, he was noted to have a petechial eruption. Curettage was performed without difficulty and the petechial eruption resolved spontaneously within 1 week. Interestingly, application of EMLA cream to the extremities and torso on two subsequent visits has failed to elicit a petechial/purpuric eruption.We thank Mrs Laurie Happel for her assistance in preparing this manuscript.