Dictionary of Allergies .. ACE inhibitors

(See Angiotensin Converting Enzyme Inhibitor): Angiotensin-converting enzyme inhibitors (ACEI) are commonly prescribed for blood pressure control and renal protection. ACE inhibitors, captopril and enalapril may cause chronic persistent cough, or angioedema and urticaria in susceptible individuals. The incidence of cough induced by angiotensin-converting enzyme (ACE) inhibitors has been reported to be 5%-20%, with less than half of affected patients requiring discontinuation due to persistent cough [1].

ACEI angioedema is a common side effect in patients who are taking ACEI. Usually this disorder is self-limited, and spontaneous episodes of apparently unprovoked angioedema stop with the discontinuation of the medication.

Some  patients need  hospitalization and even intubation are required for airway protection. The diagnosis is made clinically. There are no laboratory studies that establish the diagnosis. However, such investigations help exclude alternative diagnoses as the cause for the patient's presentation.

Conventional treatment with regimens used to control allergic angioedema is ineffective in this condition. The mechanism of ACEI-induced angioedema is thought to be related to its effect on the kallikrein-kinin system.

Kallikrein is a protease that converts high-molecular-weight kininogens into kinins, primarily bradykinin. Medications recently developed, primarily icatibant and ecallantide, to control hereditary angioedema, a disorder also associated with kallikrein-kinin activation, have been used to treat ACEI angioedema with some success [2].

References
1. Ng LP1, Goh P. Incidence of discontinuation of angiotensin-converting enzyme inhibitors due to cough, in a primary healthcare centre in Singapore. Singapore Med J. 2014 Mar;55(3):146-9.
2. Baram M1, Kommuri A2, Sellers SA2, Cohn JR2. ACE Inhibitor-Induced Angioedema. J Allergy Clin Immunol Pract. 2013 Sep-Oct;1(5):442-5. doi: 10.1016/j.jaip.2013.07.005. Epub 2013 Aug 30.
3. Gkelis’s Dictionary of Allergy, Vellerofontis Ed., Korinmthos 2014