Patient Care - Allergy & Immunology - October 2007 - (Page 16)

I Angioedema Many conditions may present in similar fashion to angioedema, although most have specific clinical characteristics that allow accurate diagnoses. there have been several reports of ARB-associated angioedema, which may occur at a higher rate than previously expected. Recently, the American Academy of Emergency Medicine issued a clinical practice guideline on the initial evaluation and management of patients presenting with acute urticaria or angioedema. The guideline advises that ARBs not be considered a safe alternative for patients who have experienced ACEI angioedema.12 1970s. Since then, their use has been shown to reduce mortality in patients who have hypertension or congestive heart failure and in those who are at high risk for cardiovascular events. ACEI–associated angioedema is a rare, potentially life-threatening side effect of treatment with ACEIs. Reactions range from mild swelling of the face, hands, feet, or bowel to life-threatening airway compromise. The most common sites of involvement are the lips, tongue, and face.9 The highest incidence is during the first month of treatment with an ACEI, but the majority of cases occur past the first month and up to years later.10 The exact mechanism of ACEI-associated angioedema remains to be elucidated. Angiotensin converting enzyme inactivates bradykinin, and the inhibition of this process could contribute to angioedema. Treatment includes advanced airway management with intubation or cricothyroidotomy as indicated. Discontinuing use of the offending ACEI is important, and administration of complement C1 inhibitor or fresh-frozen plasma can be beneficial. This angioedema is a class effect, so discontinuation of the ACEI and avoidance of other drugs from the same class should prevent any further attacks. Angiotensin receptor blockers (ARBs) may be an alternative for patients with ACEI-associated angioedema, as the rate of angioedema in patients taking ARBs is not significantly increased over that observed in the general public and appears to be less that the rate in those taking ACEIs.11 However, Angioedema associated with allergic reactions Angioedema from allergic reactions is the most commonly seen form of angioedema and often manifests in association with urticaria. The pathophysiology for angioedema and urticaria is similar as both are a result of the release of histamine and other inflammatory mediators. A key difference is the location of the edema. With angioedema, swelling involves tissues deep to the dermis, while urticaria involves swelling of tissues superficial to the dermis. Also, the lesions of angioedema are not typically associated with pruritis.6 Diagnosis is made on clinical presentation. Most angioedema from allergic reactions is due to exposure to certain foods, medications or drugs, chemicals, insect bites, environmental conditions, transfusions, or other medical conditions.13 As with other forms of angioedema, the face, lips, mouth, and extremities are primarily affected. Associated edema of the larynx is an immediate life threat and the most common cause of death with this type of reaction. Patients often complain of hoarseness, dysphagia, or the sensation of a lump in the throat and may have overt stridor. Uvular edema is felt to be a marker for concurrent laryngeal edema. Other clinical findings are more directly related to urticaria and generalized histamine release. Bronchospasm, rhinitis, conjunctivitis, tachycardia, hypotension and distributive shock, and GI symptoms may also be present. Treatment includes careful attention to airway man- 16 PATIENT CARE ALLERGY & IMMUNOLOGY www.patientcareonline.com http://www.patientcareonline.com

Table of Contents Feed for the Digital Edition of Patient Care - Allergy & Immunology - October 2007

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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