How Not to Be Misled by Disorders Mimicking Angioedema: A Review of Pseudoangioedema

Background: Angioedema is a vascular reaction involving the lower dermis, subcutis and/or submucosal tissue and causing a temporary localized swelling in any part of the body. For many health care professionals, the diagnosis presents an ongoing challenge; several disorders may manifest with subcutaneous or submucosal swelling and falsely be assumed to be angioedema. The clinicians at the emergency department and in the immunology/allergy clinics must be skilled at recognizing the features of angioedema and its differential diagnosis. Methods: The review is based on a literature search with specific indexing terms in PubMed, a review of bibliographies and the authors' clinical experience. Results: The most essential diseases that mimic angioedema, the so-called pseudoangioedemas, will each be discussed and illustrated by clinical photos, pointing out key features that help clarify the diagnoses and differentiate these from classic angioedema. Conclusions: A variety of dermatologic conditions can cause swelling that resembles angioedema, some with a potentially fatal outcome if misdiagnosed. Knowledge of pseudoangioedema is fundamental in the emergency setting when handling patients with edema and should be kept in mind when assessing an atypical angioedema case.