Which term describes an itchy, swollen lesion often caused by an insect bite or skin allergy?

The term that describes an itchy, swollen lesion often caused by an insect bite or skin allergy is "wheal." Wheals are characterized by raised, pale areas on the skin that can be itchy and are typically a result of an allergic reaction or irritation. When the skin reacts to allergens, histamines are released, leading to localized swelling and redness, forming a wheal.

In contrast, the term "scar" refers to the mark left on the skin after a wound has healed, which does not involve swelling or itchiness. "Excoriation" describes a scratch or abrasion on the skin, often resulting from picking at a lesion but does not specifically refer to the itchy, swollen nature of a wheal. An "ulcer" is a more severe skin condition, often presenting as a deep loss of skin or tissue, typically accompanied by pain rather than the itchiness and localized swelling characteristic of a wheal.