A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in area from a pinhead to 1 cm. Papules can be brown, purple, pink or red in color, and can cluster into a papular rash. They may open when scratched and become infected and crusty. Larger non-blisterform elevated lesions may be termed nodules. Papules are sometimes associated with other features such as crusts or scales.