SKIN IQ: Primary and Secondary Lesions Section Editor(s): Hess, Cathy Thomas BSN, RN, CWOCN, Department Editor Advances in Skin & Wound Care: January-February 2005 - Volume 18 - Issue 1 - p 19 InfoLink: Clinical Advisor Free Article OutlineOutline Identifying Primary and Secondary Skin Lesions Primary lesions Secondary lesions Source Back to Top | Article Outline Identifying Primary and Secondary Skin Lesions Primary skin lesions are present at the onset of a disease. In contrast, secondary skin lesions result from changes over time caused by disease progression, manipulation (scratching, picking, rubbing), or treatment. These 2 types of skin lesions can be differentiated as follows: Back to Top | Article Outline Primary lesions Bulla—a vesicle (see definition below) greater than 5 mm in diameter Cyst—an elevated, circumscribed area of the skin filled with liquid or semisolid fluid Macule—a flat, circumscribed area; can be brown, red, white, or tan Nodule—an elevated, firm, circumscribed, and palpable area greater than 5 mm in diameter; can involve all skin layers Papule—an elevated, palpable, firm, circumscribed area generally less than 5 mm in diameter Plaque—an elevated, flat-topped, firm, rough, superficial papule greater than 2 cm in diameter; papules can coalesce to form plaques Pustule—an elevated, superficial area that is similar to a vesicle but filled with pus Vesicle—an elevated, circumscribed, superficial, fluid-filled blister less than 5 mm in diameter Wheal—an elevated, irregularly shaped area of cutaneous edema; wheals are solid, transient, and changeable, with a variable diameter; can be red, pale pink, or white. Back to Top | Article Outline Secondary lesions Crust—a slightly elevated area of variable size; consists of dried serum, blood, or purulent exudate Excoriation—linear scratches that may or may not be denuded Lichenification—rough, thickened epidermis; accentuated skin markings caused by rubbing or scratching (eg, chronic eczema and lichen simplex) Scale—heaped-up keratinized cells; flakey exfoliation; irregular; thick or thin; dry or oily; variable size; can be white or tan. Back to Top | Article Outline Source Hess CT. Clinical Guide: Wound Care. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005. © 2005 Lippincott Williams & Wilkins, Inc.