It changes rapidly in size due to shifting edema in the dermis. Nodule - a round or ellipsoid palpable solid lesion which is deeper than a papule. Pustule - a circumscribed elevation of the skin that contains a purulent exudate. Cyst- a closed cavity that contains liquid or semisolid material. Scale - desquamating layers of stratum corneum.
Crusts are a sign of pyogenic infection.
Erosion - an area with circumscribed denudation due to epidermal loss. Lichenification - skin thickening that is the result of chronic rubbing leading to accentuation of normal skin lines. Atrophy- epidermal atrophy results from a decrease in the number of epidermal cell layers. Dermal atrophy results from a decrease in the dermal connective tissue. Excoriation - superficial excavations of the epidermis that result from scratching.