What is a pustule?

A pustule is defined as a pus-filled lesion, which is a raised, inflamed bump on the skin that is often red and contains pus. This pus is typically a mixture of dead white blood cells, bacteria, and other debris that accumulate in response to infection or inflammation. Pustules are commonly seen in conditions like acne, folliculitis, or certain dermatoses, indicating that there is an ongoing inflammatory process in the skin.

The other options describe different skin conditions. Skin cancer refers to abnormal growth of skin cells that can occur for various reasons, including UV exposure, but it is not characterized as a pustule. An area of skin discoloration can refer to many different dermatological conditions, such as hyperpigmentation or hypopigmentation, but does not relate to the presence of pus. A fungal infection tends to involve fungal organisms affecting the skin, leading to different types of lesions that are not specifically defined as pustules. Understanding these distinctions helps in identifying skin conditions accurately and offers insight into their management.