ACE and anaphylaxis: ,12 Risk factors that increase the severity of anaphylaxis include the delay in the use of epinephrine, followed by the severity of the reaction, absence of urticaria, biphasic reaction, use of beta-blockers or angiotensin converting enzyme inhibitors, age over 65 years, cardiovascular or lung disease, uncontrolled asthma, drug-induced anaphylaxis, elevated serum tryptase, and platelet activating factor deficiency.12