Facial angioedema and systemic lupus erythematosus: case report.

Non-medication-related acquired deficiencies of C1 esterase inhibitor (C1-INH) can cause the facial acquired angioedema (AAE) seen in systemic lupus erythematosus (SLE). The defect can originate from a lymphoproliferative disease (LPD) that catabolizes C1-INH or from circulating antibodies that inactivate C1-INH. This report describes a third and rare variety of facial AAE originating in SLE in which there was no LPD or circulating antibodies to impede C1-INH activity.