An asthmatic patient develops wheezing and lip swelling after a rubber dam is placed. What is the most appropriate emergency treatment?

The combination of wheezing and angioedema (lip swelling) following rubber dam placement is consistent with latex-induced anaphylaxis — a Type I (IgE-mediated) immediate hypersensitivity reaction to latex proteins. Epinephrine (0.3 mg intramuscularly into the anterolateral thigh using an auto-injector) is the first-line and life-saving treatment for anaphylaxis. It reverses bronchospasm, reduces mucosal edema, and prevents cardiovascular collapse via alpha-1 and beta-1/beta-2 receptor stimulation. EMS should be activated immediately. Antihistamines and corticosteroids are adjuncts and do not treat the acute anaphylactic reaction. Albuterol addresses bronchospasm only; it does not treat systemic anaphylaxis.