A furuncle is a bacterial or fungal infection of a hair follicle. The infected hair follicle can be on any part of the body. When the hair follicle becomes infected, the skin around it also becomes inflamed, so the furuncle looks like a red, raised bump on the skin, but can later rupture and weep ...
Blisters are actually vesicles and bullae. Vesicles are circumscribed epidermal elevations in the skin containing clear fluid and mesuring less than 0.5 cm. in diameter. If the lesion has a diameter greater than 0.5 cm, it is called a bulla.
A wheal is an evanescent rounded or flat-topped elevation in the skin that is edematous, and often erythematous. They may vary in size from a few mm. to a few cm. The shape may change and these lesions are usually pruritic (itchy).
A plaque is an elevated area of skin 2 cm. or more in diameter. It may be formed by a coalescence of papules or nodules. The surface area is greater than its height. It is a plate-like lesion.
Nodules are forms of papules, but are larger and deeper. They may be located in the dermis or subcutaneous tissue, or in the epidermis. Nodules are usually 0.5 cm. or more in diameter.
A papule is a solid, elevated lesion with no visible fluid which may be up to 0.5cm. in diameter. The elevation may be accounted for by metabolic deposits, infiltrates, or hyperplasia of cellular elements, etc.
A pustule is a circumscribed elevation of the skin that contains a purulent exudate that may be white, yellow, or greenish-yellow in color.
Are circumscribed alterations in skin color. The skin surface is neither elevated or depressed in relation to the surrounding skin. Macules may be of any size or color. White, brown, and red are the most common color changes seen in macules.
