TYPES OF SKIN LESIONS
a. General Information. Generally, while the epidermis plays a leading role in
the skin by being the barrier between the human's internal tissues, and so forth, and the
environment, the dermis is the more indispensable. Of the two layers, the dermis is
much thicker and measures up to four mm in depth. The dermis is composed of
collagenous and elastic tissues. These tissues provide the structural base for the
epidermis as well as a site for vascular and nerve networks in the skin. Alteration in any
component of the skin-- epidermis, dermis, or any skin appendage--can result in
clinically visible skin lesions.
b. Types of Skin Lesions. Skin lesions can be divided into three categories:
primary skin lesions, secondary skin lesions, and special skin lesions. Primary skin
lesions are basic and simple. Secondary skin lesions result from complications of
primary skin lesions.
c. Primary Skin Lesions.
(1) Macule. A macule (figure 3-3) is a definite area of skin in which the skin
color has changed from the normal skin color. This area is neither higher nor lower than
the surrounding skin area. These flat, discolored spots are either hypopigmented
(abnormally diminished in pigmentation) or hyperpigmented (abnormally increased in
pigmentation). The lesions are of varied size, less than one milliliter in diameter.
Macules may be adjacent to each other and cover a whole extremity (for example, a
leg) or half of the face (as in the disease capillary hemangioma). Macules may be cafe
au lait colored (color of coffee with milk) as in Albright's syndrome, blue to black as in
urticaria (hives), or white as in certain forms of leprosy.
Figure 3-3. Macule.
(2) Papule. A papule (figure 3-4) is a solid, elevated lesion usually 0.5 cm
to 1 cm or less in diameter. Most of the lesion is above the level of the surrounding skin
rather than deep within the skin. Many skin diseases start with papules--warts,
psoriasis, syphilis, drug eruptions, and some phases of acne. Different types of papules
are different colors. The papules of psoriasis are flat-topped and red, often with a