Final answer:
In dermatology, a plaque is an elevated, flat-topped skin lesion larger than 1 cm, often associated with conditions like psoriasis and can result from an inflammatory response to damage or infections of the skin.
Step-by-step explanation:
A plaque in dermatology refers to a type of skin lesion that is characterized by an elevated, flat-topped area on the skin, which is larger than 1 cm in diameter. Plaques may vary in color and can be a symptom of various dermatological conditions, including psoriasis, eczema, and some types of skin cancer. Plaques are commonly associated with an inflammatory response and can result from other conditions like contact dermatitis or infections that affect the hair follicles leading to conditions like folliculitis. The formation of plaques is often associated with damage to the skin barrier, allowing microbes to infect deeper tissue and potentially causing systemic infections if they enter the bloodstream.