Hereditary Angioedema (HAE): This condition is characterized by recurrent episodes of angioedema, often without urticaria, and can be associated with elevated IgA levels in some cases. The lack of response to antihistamines or corticosteroids and a family history can support this diagnosis.

Acquired Angioedema (AAE): This can be due to various causes including lymphoproliferative disorders, autoimmune diseases, or the use of certain medications like ACE inhibitors. Elevated IgA could be seen in the context of an underlying lymphoproliferative disorder.
Allergic Reactions: Although less common with isolated IgA elevation, severe allergic reactions can cause facial angioedema. The presence of other symptoms like urticaria, pruritus, or a clear allergen exposure history would support this diagnosis.

Malignancy-associated Angioedema: Certain malignancies, particularly those of lymphoid origin, can lead to angioedema through various mechanisms, including the production of autoantibodies or immune complexes. Missing this diagnosis could delay the treatment of an underlying cancer.
Autoimmune Disorders: Conditions like systemic lupus erythematosus (SLE) or rheumatoid arthritis can occasionally present with angioedema and elevated IgA levels due to immune complex formation or other immune dysregulation mechanisms.

Gleich Syndrome (Eosinophilic Angioedema): A rare condition characterized by episodic angioedema associated with eosinophilia, which could potentially be linked to elevated IgA levels in some cases.
Idiopathic Angioedema: This diagnosis is considered when angioedema occurs without an identifiable cause, including allergies, autoimmune diseases, or hereditary conditions. Elevated IgA might be an incidental finding in such cases.