Acquired angioedema (AAE) is a rare condition caused by C1 inhibitor deficiency, clinically characterized by the onset of acute episodes of predominantly facial edema without an obvious trigger, with potential upper airway obstruction. The main underlying etiologies are hematological malignancies such as monoclonal gammapathy of undetermined significance and B-cell non-Hodgkin lymphomas. Diagnosis requires a high level of clinical suspicion and should be considered when AAE episodes appear later in life. We present the case of an elderly woman who experienced episodes of AAE, initially diagnosed as anaphylactic reactions to various triggers. During the evaluation, she was diagnosed with marginal zone lymphoma, with the occurrence and resolution of AAE episodes being directly linked to the therapy and recurrence of the lymphoma.