7: Efficacy of Topical Lidocaine Preparations In Spontaneous Rupture of Uncomplicated Skin Abscesses

Article Outline

• Study Objectives
• Methods
• Results
• Conclusion
• Copyright

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Study Objectives 

To determine the incidence of spontaneous drainage of superficial skin abscesses following the application of a topical lidocaine preparation (TLP), and whether management of these infections with manual expression of pus only is associated with worse outcomes than formal incision and drainage (I&D) procedures.

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Methods 

This was a prospective cohort study of patients aged six months to 18 years with uncomplicated skin abscesses presenting to an ED or outpatient clinic. All children were enrolled between September 2006 to May 2009 in the setting of a randomized, controlled trial to compare the efficacy of seven days of cephalexin versus clindamycin, with follow-up at 48 to 72 hours and at 7 days. Clinical information obtained at time of study enrollment included: history of spontaneous drainage prior to presentation, size of induration, size of erythema, presence of pain/tenderness, and presence of fevers. Clinical management, including use of a TLP and type of subsequent procedure, was at the discretion of the treating provider. During the study period, the standard TLP used at our institution was 4% lidocaine cream (LMX-4). Per nursing policy, a bio-occlusive dressing was used after application of a TLP and left in place for at least 30 minutes. Patients were categorized as improved at 48-72 hours if there was improvement in the following variables (without worsening in any): fevers, erythema, pain/tenderness, and drainage. Resolution at 7 days was defined as resolution of all of the four variables.

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Results 

200 children were enrolled as part of the larger randomized, controlled trial, and of these 156 received a TLP. 81/156 (52%) of those who received a TLP and 5/44 (11%) of those who did not receive a TLP had a history of spontaneous drainage prior to presentation. Among those with a history of spontaneous drainage and who received a TLP, 40/81 (49%) had re-opening of their infections with manual expression of pus as their only subsequent procedure; 39/81 (48%) had a formal I&D procedure, while 2/81 (2%) had no procedure. Among those without a history of spontaneous drainage and who received a TLP, 17/75 (23%) had spontaneous rupture of their abscess after application of a TLP with manual expression of pus only; 56/75 (75%) had a formal I&D procedure, while 2/75 (3%) had no procedure.

Of the 57 patients who had spontaneous drainage after application of a TLP and manual expression of pus as the only subsequent procedure, 56/57 (98%) were improved by the 48-72 hour visit, and 55/57 (96%) had complete resolution by the 7-day follow-up. Of the 95 patients who had an I&D procedure after application of a TLP, 88/95 (93%) were improved by the 48-72 hour visit, and 93/95 (98%) had complete resolution by the 7-day follow-up. There was no significant difference in outcomes at 48-72 hours (p=0.26) or 7 days (p=0.27) between the groups which had manual expression of pus versus those who had formal I&D procedures after application of a TLP.

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Conclusion 

The use of a topical lidocaine preparation with bio-occlusive dressing promotes spontaneous drainage of superficial skin abscesses among those with and without a history of prior drainage. There was no significant difference in outcomes among patients who had manual expression of pus after application of lidocaine versus those who had formal incision and drainage procedures.