Patient Care - Allergy & Immunology - October 2007 - (Page 15)

Angioedema I Diagnosis is based on a history of episodic occurrence of nonpruritic swelling involving the skin, GI, and upper respiratory tracts that frequently starts in childhood but can present later in life. Family history can be contributory. Routine laboratory studies are usually normal with frequent leukocytosis with GI episodes. Complement 2 and 4 levels are the most reliable indicators of the condition since they are decreased in both type 1 and type 2 HAE. Treatment of acute exacerbations includes fluid replacement if severe volume contraction is present. Special attention should be paid to laryngeal involvement that might require intubation or tracheostomy. HAE is more refractory than allergyrelated angiodema to the use of corticosteroids and SC epinephrine. Commercially available C1 esterase inhibitor is available for infusion, or freshfrozen plasma can be used to replace the missing C1 inhibitor protein.7 Prophylactic treatment with androgenic agents, such as danazol (Danocrine) and stanozolol (Winstrol), has been shown to reduce attacks by increasing C4 complement levels. Most common side effects include arterial hypertension, hepatic toxicity, lipid profile changes, and virilization in women that can be minimized by using the smallest effective dosage. Treatment for children must take into account age-related anatomic and physiologic differences.8 Other prophylactic agents for HAE include aminocaproic acid (Amicar). CLINICAL PEARL Treatment of angioedema related to allergic reactions includes careful attention to airway management, with intubation or other techniques for securing the airway being of paramount importance. Acquired angioedema Acquired angioedema (AAE) is a rare condition that is set apart from HAE by the absence of family history of angioedema. The clinical presentation is the same and consists of painless, nonpruritic swelling of the skin and mucosal surfaces. AAE is classified into type 1 and type 2. The first type is associated with the presence of other diseases including multiple myeloma, chronic lymphocytic leukemia, Waldenstöm’s macroglobulinemia, non-Hodgkin’s lymphoma, and infections with Helicobacter pylori. The production of complementactivating factors, antibodies, and immune complexes by the associated diseases destroys the function of C1 inhibitor and results in angioedema. In type 2, for unknown reasons, there is a subpopulation of B cells that secretes autoantibodies to C1 inhibitor protein. Diagnosis is made with the history of the associated diseases and laboratory studies that show decreased levels of C1 inhibitor, C1, C2, and C4 complement. A positive immunoblot assay for cleavage products of C1 inhibitor protein is available for type 2.6 Treatment is supportive in acute exacerbations with the goal of treating the underlying disorder. Therapy significantly reduces future attacks but does not eliminate them completely. For type 2 AAE, plasmapheresis and cyclophosphamide immunosuppressive therapy directed at decreasing autoantibody production may be effective. ACE-inhibitor-associated angioedema The antihypertensive drugs known as ACE inhibitors (ACEIs) were developed from a hypotension-inducing substance found in the venom of the Brazilian pit viper (Bothrops jararaca) during the OCTOBER 2007 PATIENT CARE ALLERGY & IMMUNOLOGY 15

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Patient Care - Allergy & Immunology - October 2007 Research Digest Contents Medicine in the News When to Suspect Celiac Disease and How to Proceed From There Averting Angioedema’s Potentially Dire Consequences Is There a Role for Leukotriene Receptor Antagonists in Treating Allergic rhinitis? Clinical Clips Dermatology Case Challenge Classified Advertising

Patient Care - Allergy & Immunology - October 2007

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