What type of lesion is typically itchy and swollen due to an allergy?

The type of lesion that is typically itchy and swollen due to an allergy is a wheal. Wheals are raised, palpable lesions that often appear as smooth, swollen areas on the skin. They are commonly associated with allergic reactions, such as those triggered by insect bites, certain foods, or medications. The swelling occurs because of fluid accumulation in the dermis, which is a response from the body's immune system to allergens. This fluid shift is what makes wheals both itchy and raised.

In contrast, pustules are filled with pus and are frequently indicative of infection or acne; macules are flat, discolored spots on the skin that do not have elevation or itching; and nodules are solid, raised lesions that typically extend deeper into the skin's layers and are not primarily associated with an itchy sensation. Therefore, the characteristics of wheals align perfectly with the description provided in the question.