Skin necrosis following local anesthetic: Same presentation for two different diagnoses

Local anesthetics (LA) are widely used in medicine and are generally well tolerated. Although most adverse reactions are nonallergic, LA are a frequent reason for allergy consultation.

We want to expand the differential diagnosis of adverse reactions to LA by presenting rare diagnoses.

We present here two patients with similar clinical presentations, namely skin necrosis after local anesthesia with lidocaine, but with two different final diagnoses.

For Patient 1, skin necrosis was imputed to the vasoconstrictor effect of epinephrine in a patient with vascular background aggravated by heavy consumption of tobacco and cannabis. Patient 2 final diagnosis was Nicolau syndrome (embolia cutis medicamentosa), a cutaneous necrosis at the site of injection.

The allergist should be aware of these diagnoses and include them in the differential diagnosis of local anesthetic hypersensitivity.