Final answer:
A pustule is a small, elevated, pus-filled skin lesion that is a localized inflammatory response to infection or skin damage, often seen in conditions like acne and impetigo.
Step-by-step explanation:
The level of response for a pustule is a localized dermatological reaction that occurs in the skin as a form of inflammatory response to damage or infection. Pustules are small, elevated lesions that contain pus and are often a sign of conditions like acne or impetigo. In impetigo, pustules along with vesicles and bullae, can rupture to form crusty sores, usually around the nose and mouth. These pustules can be a response to infection by bacteria such as Staphylococcus aureus or Streptococcus pyogenes. On the other hand, acne pustules are typically due to the infection of hair follicles by Propionibacterium acnes, resulting in inflamed, pus-filled lesions.