HAE Diagnosis/Treatment
Differentials
Biologics
Pathophysiology
Pearls
100

This screening laboratory abnormality is almost always present between attacks in classic HAE due to C1 inhibitor deficiency.

What is a low C4 level?

100

Recurrent angioedema without urticaria, abdominal pain, and a family history should prompt evaluation for this condition.

What is hereditary angioedema?

100

This anti-IgE monoclonal antibody is first-line biologic therapy for antihistamine-refractory CSU.

What is omalizumab?

100

The primary mediator of swelling in hereditary and acquired C1 inhibitor deficiency.

What is bradykinin?

100

CSU is defined by urticaria occurring most days of the week for at least this duration.

What is 6 weeks?

200

Two laboratory tests that differentiate Type I from Type II HAE.

What are C1 inhibitor antigen level and C1 inhibitor functional assay?

200

Urticaria lasting >24 hours with residual hyperpigmentation and possible systemic symptoms suggests this diagnosis.

What is urticarial vasculitis?

200

The standard, guideline-supported dose of omalizumab for CSU.

What is 300 mg every 4 weeks?

200

This system generates bradykinin through activation of factor XII and plasma kallikrein.

What is the contact system?

200

Up-dosing of this medication class (up to 4× standard dose) is first-line therapy for CSU.

What are second-generation H1 antihistamines?

300

This complement component helps distinguish acquired C1 inhibitor deficiency from hereditary disease.

What is C1q?

300

Neutrophil-predominant urticaria should prompt evaluation for this autoinflammatory syndrome associated with IgM gammopathy.

What is Schnitzler syndrome?

300

This BTK inhibitor showed high efficacy for CSU in recent network meta-analysis but has less certain long-term safety.

What is remibrutinib?

300

In CSU, mast cell activation commonly results in release of this mediator responsible for pruritus.

What is histamine?

300

Angioedema plus wheals in CSU does not exclude this mechanism.

What is mast cell–mediated disease?

400

These medications are ineffective for acute swelling in bradykinin-mediated angioedema.

What are antihistamines, corticosteroids, and epinephrine?

400

This medication class is a common cause of nonhistaminergic angioedema, particularly in African American patients.

What are ACE inhibitors?

400

This IL-4 receptor antagonist improves itch and wheals in CSU but lacks angioedema-specific trial data.

What is dupilumab?

400

IgG autoantibodies directed against this receptor support an autoimmune subtype of CSU.

What is FcεRIα?

400

Sensitivity to this medication class is associated with prolonged and more severe CSU. 

What are NSAIDS?

500

This class of medications directly targets the bradykinin pathway and is effective for acute HAE attacks.

What are C1 inhibitor replacement or bradykinin-pathway agents (e.g., icatibant)?

500

Normal C1 inhibitor levels, estrogen sensitivity, and mutations in FXII characterize this subtype of angioedema.

What is HAE with normal C1 inhibitor (HAE-nl-C1INH)?

500

This immunosuppressant may be highly effective for CSU but is associated with increased adverse events.

What is cyclosporine?

500

This biologic pathway explains why antihistamines fail in bradykinin-mediated angioedema.

What is non–mast cell–mediated vascular permeability?

500

This type if prophylaxis is recommended before dental procedures or surgery in patients with HAE

What is short-term prophylaxis with C1 inhibitor?