A patient develops lip swelling immediately after a rubber dam is removed. The swelling is diffuse, painless, and non-pitting. What is the most likely diagnosis?

Angioedema is a deeper form of allergic reaction (Type I IgE-mediated hypersensitivity) involving rapid swelling of the dermis, subcutaneous, and submucosal tissues. When it occurs after rubber dam removal, it strongly suggests a latex allergy. Natural rubber latex (NRL) contains proteins that can trigger IgE-mediated reactions in sensitized individuals, ranging from contact urticaria and angioedema to systemic anaphylaxis. Angioedema characteristically presents as diffuse, painless, non-pitting swelling — unlike contact dermatitis (which causes erythema, vesicles, and itching) or traumatic edema. All dental offices should have latex-free alternatives available and should screen patients for latex allergy.