Case report: foot angioedema due to the application of topical antibiotic to a surgical wound

Riccardo Garcea *

Abstract: The application of a topical antibiotic to a surgical suture is a practice that allows a reduction of site infections, but it m ay present risks of allergic reactions, especially if new formulations of topical therapies are used. The article reports a case of rare a ngioedema of an operated foot, due to an allergic reaction to sulfonamides applied over the suture on a 58 ­ year ­ old woman who did not report a previous allergic reaction that occurred 42 years before due to the intake of cotrimoxazole. The article analyzes the possibility that t he new therapeutic formulations (hydrogels, ointments, nanoparticles, liposomes ...) can promote a greater absorption and penetration of th e product, but also may be associated with a possible more intense allergic reaction.

Key words: angioedema, surgical site infection, topical antibiotics.

Key messages:

• describe an atypical case of angioedema and analyze the major potential allergic risks of topical therapies’ new formulati ons.

Introduction

The use of topical antibiotics after a surgical suture not only it is commonly used but it is also recognized in the literature (1) and it is associated with a 4050% reduction of surgical site infections compared to no topical therapy or antiseptics. In addition to traditional creams, products with a more "physiological" formulation are now on the market, products such as ointments and even hydrogels, which with the active ingredient conveyed in liposomes or nanoparticles, they offer a better diffusion of the active ingredients into the epidermis.

Although the anaphylactic risks of topical therapy are very rare and mainly characterized by erythema, a correct medical history remains essential in order to avoid occasional and uncomfortable allergic reactions.

The choice of using a topical product that associates an antibiotic to silver originates from the widespread use of this product since the 1960s. While 6,000 years ago (2) metal was known as a therapeutic agent; the "oneshot" application is useful for cleaning up the surgical site (especially in a dirtier area), avoiding the problems caused by a possible cytotoxicity of the product (3).

The application on the skin covered with a non ­ ad gauze containing hyalu ­ ronic acid improves humidity in "dry" skin areas, such as the palms of the hands and the soles of the feet.

This article reports an uncommon case of angioedema of the foot, which occurred following a single application of hydrogel with silver sulphadiazine on the surgical wound of a patient who had forgotten to report a skin erythema of the trunk at the age of 16, after some days of oral therapy with sulfamethoxazole and trimethoprim .

This kind of episodes are to be considered “atypical”, due to their reduced frequency (4) and are generally mediated by mast cells, characterized by a rapid onset due to the release of histamine, followed by a complete resolution in 24­48 hours (5).

* L.t. Col. MD Head of Health Section and professor of the Military Medicine chair of the Carabinieri Officers School, Rome. Corresponding author: Email: riccardo.garcea@carabinieri.it