Topical anesthetic cream is associated with spontaneous cutaneous abscess drainage in children

Unlabelled imageTopical anesthetic cream is associated w”>American Journal of Emergency Medicine (2012) 30, 104-109

Original Contribution

Topical anesthetic cream is associated with spontaneous Cutaneous abscess drainage in children?,??,?

Tara Cassidy-Smith MD a, Rakesh D. Mistry MD, MS b, Christopher J. Russo MD c,d, Kathryn McCans MD a, Naomi Brown MD b, Lisa M. Capano-Wehrle MPH a,

Lisa A. Drago DO a, Patty A. Vitale MD a, Brigitte M. Baumann MD, MSCE a,?

aDepartment of Emergency Medicine, UMDNJ-RWJMS at Camden, One Cooper Plaza, Camden, NJ 08103, USA

bDivision of Emergency Medicine, Children’s Hospital of Philadelphia, PA 19104, USA

cDivision of Emergency Medicine, AI duPont Hospital for Children, Wilmington, DE 19803, USA

dDepartment of Emergency Medicine, St. Christopher’s Hospital for Children, Philadelphia, PA 19134, USA

Received 30 August 2010; revised 18 October 2010; accepted 19 October 2010


Objective: The objective of the study was to determine whether use of topical anesthetic cream increases spontaneous drainage of skin abscesses and reduces the need for procedural sedation.

Methods: A retrospective Multicenter cohort study from 3 academic pediatric emergency departments was conducted for randomly selected children with a cutaneous abscess in 2007. Children up to 18 years of age were eligible if they had a skin abscess at presentation. Demographics, Abscess characteristics, and use of a topical analgesic were obtained from medical records.

Results: Of 300 subjects, 58% were female and the median age was 7.8 years (interquartile range, 2-15 years). Mean Abscess size was 3.5 +- 2.4 cm, most commonly located on the lower extremity (30%), buttocks (24%), and face (12%). A drainage procedure was required in 178 children, of whom 9 underwent drainage in the operating room. Of the remaining 169 children who underwent emergency department-based drainage, 110 (65%) had a topical Anesthetic agent with an occlusive dressing placed on their abscess before drainage. Use of a topical anesthetic resulted in spontaneous abscess drainage in 26 patients, of whom 3 no longer required any further intervention. In the 166 patients who underwent additional manipulation, procedural sedation was required in 26 (24%) of those who had application of a topical anesthetic and in 24 (41%) of those who had no topical anesthetic (odds ratio, 0.45; 95% confidence interval, 0.23-0.89).

Conclusions: Topical anesthetic cream application before drainage procedures promotes spontaneous drainage and decreases the need for procedural sedation for pediatric cutaneous abscess patients.

(C) 2012

? Financial disclosure: There was no financial support for this investigation.

?? Prior presentation: This study was presented at the Society for Academic Emergency Medicine annual meeting. New Orleans, May 2009.

? Conflict of interest: None of the authors have any conflicts of interest.

* Corresponding author. Tel.: +1 856 968 2627; fax: +1 856 968 8426.

E-mail address: [email protected] (B.M. Baumann).

0735-6757/$ – see front matter (C) 2012 doi:10.1016/j.ajem.2010.10.020


The incidence of skin and soft tissue infections (SSTIs), especially those from community-acquired methicillin- resistant Staphylococcus aureus (CA-MRSA), has reached epidemic proportions in the previous 2 decades [1,2]. In 1993, 1.2 million skin infections were diagnosed by emergency physicians; by 2005, this number had nearly tripled to 3.4 million [3]. The pediatric population is particularly affected by the increased incidence of SSTI and often presents to the emergency department (ED) for diagnosis and definitive therapy [4]. The mainstay of therapy for simple cutaneous abscess remains to be the removal of purulent material via incision and drainage [5-10]. From a technical standpoint, successful completion of a drainage procedure is not complex; however, what is often a quick bedside procedure in an adult can become an involved procedure in children, as a result of the need for ancillary analgesic therapies and procedural sedation. Procedural sedation can be labor intensive, as it involves additional staffing, including technicians and child life therapists, advance preparation, and substantial Recovery time, which may compromise ED Patient throughput.

Through routine care in our EDs, we noted several cases of spontaneous drainage following application of topical anesthetic cream (eg, LMX) that appeared to decrease the need for procedural sedation in children who normally required drainage procedures. In light of these findings, we conducted an investigation to determine whether use of topical anesthetic cream increases spontaneous drainage of skin abscesses and reduces the need for procedural sedation.


Study design

This was a retrospective chart review of children up to

18 years of age who presented between January 1 and December 31, 2007, for a cutaneous abscess. Subjects were identified using computerized billing and data entry systems. International Classification of Diseases, Ninth Revision, codes 680.0 to 686.9 were used to identify potential subjects; and ED records were then reviewed for inclusion. Subjects were included if they had a cutaneous abscess. Patients who presented with an isolated pilonidal abscess, paronychia, or an abscess involving the genitalia were excluded [11-13]. Of this group, a random subset of 100 patients from each of the 3 centers was included. This study was approved by each center’s institutional review board.


Three sites that participated in this investigation included 2 children’s hospitals and a general hospital. The general

hospital has a nested pediatric ED located within the main ED. All 3 sites are located in urban setting and have dedicated pediatric emergency medicine-trained physicians.

Data collection and processing

The study design incorporated recommended protocols for chart review research, including case selection protocols, abstractor training, monitoring and blinding, and the use of standardized data abstraction forms [14]. Each site had a maximum of 2 trained investigators abstracting data. Demo- graphics, physical examination findings, abscess drainage procedures, and the use of anesthetic creams and conscious sedation were recorded. The topical anesthetic that was exclusively used at all sites was topical lidocaine cream that features a liposomal delivery system 4% (LMX 4; Ferndale Laboratories, Ferndale, MI). The use of a topical anesthetic cream was at the discretion of the health care providers. At each institution, the anesthetic cream was placed over the child’s cutaneous abscess and covered with an occlusive dressing for 30 to 40 minutes, as per the manufacturer’s instructions, before an incision and drainage attempt. Data regarding Spontaneous rupture and drainage of abscesses after the use of anesthetic creams, and subsequent drainage and procedural sedation, were obtained from medical records.

Data analysis

We determined that 57 subjects were needed in each group to achieve 80% power and a 2-sided ? of .05 to detect an increase in spontaneous drainage rates from 2% in children who received no Topical anesthesia to 20% in children who had an application of topical anesthesia. We allowed for at least one child (2%) in the no topical anesthesia group to experience a spontaneous drainage before procedural drainage for this sample size calculation. In our experience, this baseline rate of 2% was a conservative (high) estimate because children rarely undergo spontaneous drainage without an intervention.

Data are presented using summary statistics with means +- standard deviations for normal data or medians and interquartile ranges (IQRs) for data that were not normally distributed. For comparisons, means were compared using Student t test. Risk differences with 95% confidence intervals (CIs) were used to compare binomial outcomes such as spontaneous abscess drainage in the ED, need for procedural drainage, need for procedural sedation, and hospitalization rates. Data were analyzed using SPSS version

15.0 (SPSS, Inc, Chicago, IL).


Three hundred children comprised the study population: 175 (58%) were female, 151 (50%) were black, and 69

Table 1

Baseline characteristics of the study sample


All abscess patients (N = 300)

Children who underwent procedural drainage

Median (IQR)

Topical anesthetic a (n = 110) No topical anesthetic (n = 59)

Median (IQR) Median (IQR)

Age (y)

7.8 (2.1, 14.8)

7. 4

(2.1, 14.1)


(1.9, 16.1)


78 (26)






70 (23)






85 (28)






67 (22)





n (%)






175 (58)





Febrile (>=38?C)

52 (17)





Most common abscess sites

Lower extremity

91 (30)






71 (24)





Face or scalp

37 (12)






34 (11)






22 (7)





Surrounding cellulites

188 (63)






127 of 196 (65)

75 of 98


28 of 53



45 of 196 (23)

18 of 98


18 of 53


MSSA indicates methicillin-sensitive S aureus.

a Includes the 3 children who originally had abscesses that spontaneously drained after application of topical anesthetic.

b Reflects those patients who had cultures sent for antimicrobial sensitivity testing.

(23%) were Hispanic. Two hundred sixty-eight (89%) children had only one abscess at presentation, 23 (8%) had 2, and 9 (3%) had at least 3 lesions. The mean size of the largest abscess at presentation was 3.5 +- 2.4 cm. Patient characteristics are presented in Table 1.

169 children comprised the study population

9 drained in the operating room and not included in final analyses

178 required an incision and drainage procedure

110 received LMX

59 received nothing

Other than age, there were few differences between the topical anesthetic group and the group that did not receive topical anesthesia. There was no difference in mean pain scores at presentation (mean pain score, 4.9 +- 3.2 vs 5.4 +- 3.6; P = .05) or in mean abscess size (3.4 +- 2.4 vs 4.0 +- 2.7 cm, P =.22) between the topical anesthetic group and the group that did not receive topical anesthesia. The topical anesthesia group was more likely to have abscesses due to MRSA (77% vs 53%; percentage difference, 24% [95% CI 8% to 39%]) and less likely to have a surrounding cellulitis when compared with the group that did not receive topical anesthesia (49% vs 66%; percentage difference, -17% [95% CI, -13% to -31%]).

Of the 300 children, 178 (59%) required incision and drainage of their cutaneous abscess, per the treating ED physician. Nine were drained by the surgical service in the operating room and were excluded. The study population, therefore, was composed of 169 children who remained candidates for ED drainage procedures. One hundred ten children had a topical anesthetic agent placed on their abscess. Use of a topical anesthetic agent resulted in spontaneous drainage in 26 patients, of whom 3 no longer

100 discharged

10 admitted

50 discharged

9 admitted

59 required procedural drainage

26 spontanous drainage 3 required no additional


107 required procedural drainage

300 enrolled

Fig. 1 Flow diagram of the use of topical anesthetic cream and procedural drainage.

Table 2 Spontaneous drainage, need for procedural drainage and sedation, and final disposition


Topical anesthetic (n = 110)

n (%)

No topical anesthetic (n = 59)

n (%)

Percentage difference (95% CI)

Spontaneous drainage in ED

26 (24)


24% (14 to 32)

Need for procedural drainage

107 (97)

59 (100)

-3% (-8 to 4)

Need for procedural sedation

26 (24)

24 (41)

-17% (-32 to -3)


10 (9)

9 (15)

-6% (-18 to 4)

Differences that do not cross zero are statistically significant.

required any further manipulation. This left a total of 166 subjects who still required drainage in the ED: 107 in the topical anesthetic group and 59 in the no topical anesthetic group (Fig. 1). Use of a topical anesthetic was associated with a significantly reduced need for procedural sedation during drainage procedures compared with nonuse (24% vs 41%; odds ratio, 0.45; 95% CI, 0.23 to 0.89) (Table 2).

With respect to infecting organism, when we examined spontaneous drainage rates comparing topical anesthetic to no topical anesthetic, there were no differences in drainage rates for MRSA (39% vs 29%; percentage, difference 10% [95% CI, -13% to 29%]) or methicillin- sensitive S aureus (33% vs 39%; percentage difference,

-6% [95% CI, -34% to 24%]).

Among the 59 study subjects who did not receive topical anesthetic, 9 were admitted to the hospital. Of the 50 who were discharged to home, 17 (34%) returned for abscess care within 30 days of the index visit. None required an additional intervention. Of the 110 children who had a topical anesthetic placed, 10 were admitted to the hospital and 100 were discharged to home. Twenty-two (22%) of the patients who were discharged returned, and 2 (2%) required additional intervention as noted below. Hospital admission within 30 days of the index visit was noted for 7 subjects for treatment of abscess-related complications. Four subjects were from the topical anesthetic group, of whom 2 required additional manipulations for adequate drainage. The

3 remaining children never had application of a topical anesthetic, nor did they undergo a drainage procedure at the index visit. Their presentation appeared to be the result of Disease progression. The difference in return admission rates in children who underwent procedural drainage did not significantly differ based on application of topical anesthetic (4% vs 0; percentage difference, 4% [95% CI, -5% to 11%]).


In this investigation, we demonstrated a 42% reduction in the use of procedural sedation in children who received a topical anesthetic before anticipated abscess drainage. Moreover, the use of topical anesthetic led to avoidance of a drainage procedure in several instances. Given the temporal relationship between topical anesthesia application and spontaneous drainage and our preliminary findings, we

propose that this minimal risk option may be more than an adjunct to pain control and may even be of therapeutic value for Pediatric abscess patients.

The importance of our findings are 2-fold. First, ED visits for SSTIs have increased by 31% over the past decade, a trend that is expected to continue [15]. Second, for the majority of cutaneous abscesses, the mainstay of treatment is a drainage procedure with additional debridement for complicated or septated abscesses [5-7,9]. Abscess drainage procedures are painful and require significant Health care resources, including physician, nursing, and child life specialist time; ED space and analgesic; and, in complicated cases, anesthetic interventions [16]. With an increasing Disease burden in the pediatric population and the need for providers to effectively treat pediatric cutaneous abscesses in a timely manner, methods to avoid resource-intensive measures, such as sedation, can be of great benefit.

Because drainage procedures for cutaneous abscesses are among the most common indications for procedural sedation of children in the ED, a less resource-dependent alternative to pain control is needed [17]. The American Academy of Pediatrics recently recommended that physicians consider topical anesthetics in any patient who has a high likelihood of undergoing a nonemergent invasive procedure on intact skin in the ED, including abscess drainage [18]. Therefore, our study of topical anesthetics for skin abscesses was undertaken; and our results are promising. We demonstrated that the application of anesthetic creams was associated with a 24% rate of spontaneous drainage and, in several cases, even obviated the need for a drainage procedure. In addition, the utilization of procedural sedation was also decreased in the topical anesthetic patient group, a surprising result because these patients were of relatively younger age. With a greater proportion of 2- to 7-year-old children in the topical anesthetic group, we anticipated a greater use of procedural sedation, as these children are often less cooperative than their older counterparts [19-21]. Furthermore, health care providers may also be more sensitive to increased levels of anxiety and stress in younger-age children who are unable to fully comprehend the necessity of the ensuing medical management.

The mechanism of spontaneous drainage remains unclear, although it could be postulated that the vasodilatory properties of the lidocaine led to a break in the already taut overlying skin [22]. The moist environment created under

the bio-occlusive dressing may also play a role. Other therapeutic interventions for procedural drainage of cutane- ous abscesses include local infiltration of lidocaine and, for Younger children or more complicated abscesses, procedural sedation. Local infiltration of lidocaine often provides poor pain relief because the lower pH in infected tissue typically reduces the effectiveness of the local anesthetic. Further- more, the injection of local anesthetic into an already swollen and tender area leads to increased pain and anxiety [8,23]. Procedural sedation can safely and effectively control pain, anxiety, and patient motion; however, procedural sedation is not without risk and is a time- and labor-intensive measure, particularly in a busy ED [24]. Adverse effects associated with procedural sedation include transient hypoxemia, apnea, laryngospasm, hypotension, hypersalivation, vomit- ing, hallucinatory emergence reactions, and respiratory depression [24-28].


Our study has several limitations that warrant discussion. First, the retrospective nature of the study may have led to information bias from missing data. Specifically, it is possible that the response to topical anesthetic may not have been adequately documented. This limitation would only have yielded an underestimate of the utility of anesthetic creams because spontaneous abscess drainage due to the application of a topical anesthetic would have been underreported. On the contrary, if abscesses already had small Lead points of drainage that were not documented on the medical record, our findings may have overestimated the efficacy of topical anesthetic creams. A second limitation is that we may not have been adequately powered to demonstrate differences between patient groups. Our numbers were limited both by our sample size and also by the limited number of cultures that were conducted. Likewise, our outcome data were limited to children who presented to the original health care site. Thus, if a child obtained additional abscess care at a second ED or required admission at another hospital, we were unable to capture these presentations. Finally, we are fully aware that our sample may have suffered from selection bias, one that we were not able to identify in our analysis. It is possible that certain patient or abscess characteristics may have led providers to preferentially use or avoid topical anesthetics, which may have affected outcomes; and we acknowledge that our results would be far more compelling if they were the result of a randomized trial. The intent of this study was to further investigate and report our initial anecdotal experi- ences. Since completing this investigation, 1 of the 3 sites has implemented the use of topical anesthetic creams as standard of care for all pediatric abscess patients. Given this new protocol, our institutional review board is reluctant to approve a randomized trial, stating that such a study could result in a reduction of care for patients assigned to the control arm. It is our hope that our findings will encourage other investigators to conduct a prospective, randomized trial.


Topical anesthetic cream application before drainage procedures appears to promote spontaneous abscess drainage and may decrease the need for procedural sedation in pediatric cutaneous abscess patients. A randomized con- trolled trial with a standardized protocol for the application of the anesthetic creams should be the next step to demonstrate whether these creams are associated with spontaneous abscess rupture as well as a reduction in procedural sedation rates. As we continue to develop evidence for best practices of pediatric skin abscesses, we should be aware of the importance of the role of anesthetic creams in both actual abscess management as well as pain management.


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