<Li> Pustule: A pustule is a small elevation of the skin containing cloudy or purulent material (pus) usually consisting of necrotic inflammatory cells . These can be either white or red . </Li> <Li> Cyst: A cyst is an epithelial - lined cavity containing liquid, semi-solid, or solid material . </Li> <Li> Erosion: An erosion is a discontinuity of the skin exhibiting incomplete loss of the epidermis, a lesion that is moist, circumscribed, and usually depressed . </Li> <Li> Ulcer: An ulcer is a discontinuity of the skin exhibiting complete loss of the epidermis and often portions of the dermis and even subcutaneous fat . </Li>

Skin loss that is confined to epidermal tissue is called a