HEREDITARY ANGIOEDEMA (HAE) is a rare but serious condition affecting 1 in 50,000 individuals. Because it is a rare disease, diagnostic delay is a problem as clinicians try to link unusual symptoms with a diagnosis.

According to Mark A. Malesker, PharmD, FCCP, FCCM, FASHP, BCPS, patients who have HAE develop edematous episodes lasting 2 to 5 days in their skin, gastrointestinal tracts, or upper respiratory tracts. These episodes may reoccur every few weeks. Usually, itching is absent, and this is a key diagnostic clue: HAE does not respond to antihistamines, corticosteroids, or epinephrine as allergies do. Malesker went on to say that of the 200,000 people who have HAE globally, 8000 live in the United States.

This autosomal dominant disease manifests in different ways. HAE is most often a genetic aberration that decreases production of the enzyme C1-INH, although some patients have normal C1-INH levels but other dysfunctional enzymes. In another group, genetic defects in factor XII have been reported. Swelling from “third-spacing”—fluid shifts from the intravascular compartment to a body compartment—frequently causes hypotension.

Malesker noted that each patient’s comprehensive treatment plan must include on-demand treatment options for acute attacks, short-term prophylaxis when they face a procedure or another stressor, and long-term prophylaxis if they experience frequent attacks. Patients need specific strategies for emergency care, a medication supply at home, and education about communicating their needs when they require acute hospital-based treatment.

Symptomatic management must start within 8 hours of first symptoms and can be effective when initiated immediately. Patients will need antiemetics, opioid analgesics, and fluids. Additional options include C1 esterase inhibitor, C1 esterase inhibitor recombinant, icatibant, and ecallantide. Patients can self-administer most of these, and they can reduce and sometimes eliminate attacks.

If stressor avoidance and on-demand treatment fail to control HAE, 4 options offer long-term prophylaxis: (1) attenuated androgens, (2) antifibrinolytics, (3) C-1 esterase inhibitors, and (4) plasma kallikrein inhibitor lanadelumab-flyo. These differ in route of administration, costs, and dosing frequency.

Micaila Ruiz, PharmD, discussed the specialty pharmacist’s unique place in HAE. With an average annual cost of care at almost $410,000 per affected individual, it is noteworthy that drugs specifically developed for HAE accounted for 97% of total costs.

Ruiz stressed that the only intervention that reduces costs is appropriate pharmacotherapy, which makes a strong case for pharmacist-directed care management. Ruiz noted that specialty pharmacists must work closely with individual patients to help them identify their specific triggers and symptoms. Pharmacists will also communicate frequently with primary care providers, specialists, and nurse case managers.

The HAE Patient Declaration of Rights helps patients obtain the care that they need. After reviewing this document, pharmacists can ensure that patients have access to at least 2 standard doses of an FDA-approved therapy for on-demand treatment of acute attacks. Patients with HAE must never be required to take anabolic steroids and fail a trial before being prescribed an FDA-approved therapy, as these therapies are indispensable.