Which of the following conditions may cause swelling and itching from insect bites?

Wheals, often associated with allergic reactions, are raised, itchy areas of the skin that can result from insect bites. When an insect bites, it can introduce saliva or other substances into the skin that trigger an immune response. This response can cause localized swelling and itching, which is characteristic of wheals. They often appear suddenly and can vary in size, but they are primarily a result of inflammation and vascular reactions to allergens.

In contrast, conditions like rosacea are generally associated with chronic skin flushing and do not typically present with swelling or itching from insect bites. Eczema, which can cause itching and inflammation, is a chronic condition often triggered by irritants or allergens but does not specifically relate to insect bites. Acne primarily involves clogged pores and is not related to allergies or insect bites either.