Which condition presents with severe hives and swollen lips after taking Bactrim?

The presence of severe hives and swollen lips after taking Bactrim indicates an allergic reaction, which is a type of hypersensitivity response to the medication. In this case, the body's immune system mistakenly identifies the components of Bactrim as harmful, resulting in symptoms such as urticaria (hives) and angioedema (swelling of deeper layers of the skin, often around the lips and eyes).

While contact dermatitis may also involve rash and swelling, it typically occurs through direct contact with allergens or irritants and is not characterized by systemic symptoms like hives immediately following medication administration.

Angioedema does specifically refer to the swelling associated with a hypersensitivity reaction, particularly in response to allergens, including medications. It is a manifestation of an allergic reaction rather than a standalone diagnosis.

Anaphylaxis is a severe, potentially life-threatening allergic reaction that includes symptoms such as difficulty breathing, rapid heart rate, and hypotension, in addition to hives and swelling. Although it could be a possibility when considering severe reactions, the question does not specify the presence of other critical signs that would suggest anaphylaxis directly, making an allergic reaction the most appropriate choice in this context.

Thus, the symptoms described align best with an allergic reaction