Which skin lesion is specifically known as Urticaria?

Urticaria, commonly referred to as hives, is characterized by the presence of wheals. These wheals are raised, itchy areas of skin that can vary in size and often have a pale center. They develop rapidly and are typically a result of an allergic reaction or other stimuli affecting the skin and its underlying tissues. The fluid that enters the tissues as part of the inflammatory response forms the wheal, leading to its distinctive appearance.

The wheal can be transient, appearing and disappearing within hours and is often accompanied by other symptoms like itchiness. This aligns with the nature of urticaria, which is usually a temporary condition triggered by allergens, medications, stress, or physical stimuli.

In contrast, other lesion types such as bulla, vesicles, and excoriations have distinct characteristics that do not define urticaria. Bulla are large blisters filled with fluid, vesicles are smaller blisters, and excoriations are essentially scratches on the skin, often due to itching or skin conditions. These do not match the description or behavior of wheals found in urticaria. Thus, the association of urticaria specifically with wheals makes this answer accurate and reflective of the condition's defining features.