# Risk-Stratified Use of Topical and Infiltrative Local Anesthetics in High-Risk Dermatologic Surgery

## TL;DR

This paper provides a risk-based framework for safely using local anesthetics in high-risk dermatologic surgeries, emphasizing updated safety practices and emergency preparedness.

## Contribution

A novel, integrated risk-stratified framework for using local anesthetics in high-risk dermatologic contexts is proposed.

## Key findings

- Epinephrine use in end-arterial sites is safe with dilute concentrations and adequate perfusion.
- Topical anesthetics in barrier-compromised skin increase systemic toxicity risks, especially in vulnerable populations.
- Dilute tumescent infiltration is safer than high-dose topical therapy for large denuded areas.

## Abstract

Local anesthetics are fundamental to dermatologic practice, yet their safety profile requires nuanced understanding in high-risk contexts including end-arterial sites, barrier-compromised skin, and scenarios predisposing to systemic toxicity. This narrative review synthesizes contemporary evidence across these three interacting domains to provide an integrated, risk-stratified framework for clinical decision-making. Regarding end-arterial territories, over two decades of clinical evidence encompassing more than 200,000 digital and acral injections has effectively dismantled the historical dogma against epinephrine use in digits, nose, ear, and penis, demonstrating an excellent safety profile when dilute concentrations are used in patients with adequate perfusion, with phentolamine providing reliable rescue for rare, prolonged vasoconstriction. In barrier-compromised skin (e.g. burns, ulcers, and inflammatory dermatoses) topical anesthetics function as absorption amplifiers, with dramatically accelerated systemic uptake that can precipitate local anesthetic systemic toxicity or prilocaine- and benzocaine-induced methemoglobinemia, particularly in infants and frail elderly patients. For large, denuded areas, dilute tumescent infiltration offers a pharmacokinetically safer alternative to high-dose topical therapy. The review details systemic toxicity risk factors, recognition, and management, emphasizing that intravenous lipid emulsion therapy has transformed severe toxicity from an often-fatal event to a manageable emergency. Special considerations for pediatric and geriatric populations, drug interactions, and cumulative dosing across modalities are addressed. The overarching conclusion is that context-sensitive risk stratification which includes integrating vascular status, barrier integrity, and host pharmacokinetics combined with office preparedness including phentolamine and lipid emulsion, enables safe local anesthesia even in traditionally high-risk dermatologic scenarios.