What size defines a plaque in dermatology?

In dermatology, a plaque is specifically defined as a flat, elevated lesion that is typically larger than 0.5 cm in diameter. This characteristic allows it to stand out from other superficial skin lesions, such as papules, which are smaller and can be slightly raised or flat. The distinction of being flat is essential, as it differentiates plaques from other forms of skin abnormalities that might have a more irregular or raised appearance.

While other factors, such as being painless and well-circumscribed, may describe various skin lesions, they do not specifically define what constitutes a plaque. The size criterion of being over 0.5 cm is a definitive aspect that helps in diagnosing and categorizing skin conditions. This reliance on size and elevation plays an important role in clinical practice, guiding dermatologists in recognizing and treating skin disorders effectively.