Scoring system aims to distinguish between 2 types of angioedema
Score designed for patients on ACE inhibitors
A simple diagnostic score may help distinguish between two types of angioedema — mast cell-mediated angioedema and drug-induced nonallergic angioedema — in people taking angiotensin-converting enzyme (ACE) inhibitors, researchers said.
They described the scoring system in the study, “Angiotensin-converting enzyme inhibitor-induced angioedema: Proposal for a diagnostic score,” published in the World Allergy Organization Journal.
ACE inhibitors, a class of medications that are commonly used to help control high blood pressure, can cause drug-induced nonallergic angioedema, a type of angioedema in which swelling arises as a side effect of a medication. In this type of angioedema, swelling is typically driven by the overproduction of a signaling molecule called bradykinin, which causes fluid to leak out of blood vessels and into nearby tissues.
People taking ACE inhibitors may also develop mast cell-mediated angioedema, in which swelling develops due the activation of mast cells, immune cells involved in inflammatory and allergic reactions.
Distinguishing between these two angioedema types is important to ensure that patients receive optimal care, but doing so can be a challenge for clinicians.
Determining types of angioedema
Four scientists in France conducted an in-depth analysis of clinical data for more than 90 people with ACE inhibitor-related angioedema, looking for factors that might help readily distinguish it from the mast cell-mediated type.
They analyzed data from 49 patients who were ultimately diagnosed with drug-induced nonallergic angioedema and 44 who were diagnosed with mast cell-mediated angioedema.
The researchers identified four key variables that helped distinguish the two angioedema types. They noted that patients with drug-induced nonallergic angioedema were more likely to experience three or fewer swelling episodes before starting treatment with an ACE inhibitor, with these episodes tending to last a day or longer. Individuals with drug-induced nonallergic angioedema also were more likely to be hospitalized in an intensive care unit, while those with mast cell-mediated angioedema were more likely to experience swelling attacks after stopping the ACE inhibitor.
Based on these factors, the researchers devised a five-point scoring system. One point was attributed if the patient experienced three or fewer swelling attacks, if attacks lasted longer than 24 hours, or if the patient was hospitalized in intensive care. Two points were given if the patient stopped having swelling attacks after discontinuing the ACE inhibitor. A total score of 4 or 5 was deemed indicative of drug-induced nonallergic angioedema, whereas a score of 3 or lower is suggestive of mast cell-mediated angioedema.
Statistical analyses showed the scoring system could accurately identify patients who had a low likelihood of having drug-induced nonallergic angioedema when the total score was 2 or lower, as well as those who had a high probability of having drug-induced nonallergic angioedema when the total score was 4 or higher.
“Our diagnostic score comprises 4 simple parameters, which can be assessed rapidly at the initial consultation and then at a single follow-up consultation,” the researchers wrote.
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