C h a p t e r 4 5
Structure and Function of the Integumentum
1149
Albinism, a genetic disorder in which there is com-
plete or partial congenital absence of pigment in the
skin, hair, and eyes, is found in all races. Although
there are over 10 different types of albinism, the most
common type is recessively inherited oculocutaneous
albinism, in which there is a normal number of mela-
nocytes but they lack tyrosinase, the enzyme needed for
synthesis of melanin. It affects the skin, hair, and eyes.
Individuals have pale or pink skin, white or yellow hair,
and light-colored or sometimes pink eyes. Persons with
albinism have ocular problems, such as extreme sensi-
tivity to light and refractive problems. Treatment efforts
for people with albinism are aimed at reducing their risk
for skin cancer through protection from solar radiation
and screening for malignant changes. Efforts to manage
the vision impairment, such as glasses, preferential seat-
ing in classrooms, and large-print books, are important.
Vitiligo
is a pigmentary problem of concern to darkly
pigmented persons of all races. It may be an autoim-
mune disease, a genetic defect, an excessive reactive
oxygen species, a calcium imbalance, or any combina-
tion of these; all are being studied. Vitiligo also affects
fair-skinned persons, but not as often, and the effects
usually are not as socially problematic. The classic sign
of vitiligo is the sudden appearance of white patches
on the skin. The lesion is a depigmented macule with
definite smooth borders on the face, axillae, neck, or
extremities (Fig. 45-9). The patches vary in size from
small macules to ones involving large skin surfaces. The
large macular type is more common. Depigmented areas
appear white, pale colored, or sometimes grayish-blue.
Histologically, the depigmented areas may contain no
melanocytes, greatly altered or decreased numbers of
Circumscribed, flat,
nonpalpable changes
in skin color
Palpable elevated
solid masses
Circumscribed superficial
elevations of the skin
formed by a fluid-filled
cavity within the skin layers
Macule
—Small, flat spot, up
to 1.0 cm
Examples: freckle, petechia
Patch
—Larger than 1.0 cm
Example: vitiligo
Papule
—Up to 1.0 cm
Example: an elevated nevis
Plaque
—Elevated superficial
lesion 1.0 cm or larger, often
formed by coalescence of
papules
Nodule
—Marble-like lesion
larger than 0.5 cm, often
deeper and firmer than papule
Wheal
—A somewhat irregular,
relatively transient, superficial
area of skin edema
Examples: mosquito bite, hive
Vesicle
—Up to 1.0 cm;
filled with serous fluid
Example: herpes simplex
Bulla
—1.0 cm or larger;
filled with serous fluid
Example: 2nd degree burns
Pustule
—Filled with pus
Examples: acne, impetigo
FIGURE 45-8.
Primary lesions may arise in previously normal skin. Authorities vary somewhat on
their definition of skin lesions by size. (Adapted from Bickley LS, Szilagyi PC. Bates’ Guide to Physical
Assessment and HistoryTaking. 8th ed. Philadelphia, PA: Lippincott Williams &Wilkins; 2003:103.)
FIGURE 45-9.
Vitiligo with various shades of hypopig
mentation, depigmentation, and islands of spontaneous
repigmentation. (From Goodheart HP. Goodheart’s Photoguide
to Common Skin Disorders. 3rd ed. Philadelphia, PA: Wolters
Kluwer Health | Lippincott Williams &Wilkins; 2008:275.)
