1162
U N I T 1 3
Integumentary Function
water loss and dry skin; and immunoglobulin E (IgE)-
mediated sensitization to food and environmental anti-
gens.
27,28
Whether the primary defect is dermatologic or
immunologic is uncertain. It has been suggested that the
epidermal barrier disturbance allows increased antigen
absorption and contributes to the hyperreactivity char-
acteristic of atopic dermatitis.
27,28
The lesions of atopic dermatitis are usually character-
ized by erythematous papules and vesicles, erosions, and
serous exidates. Scratching causes crusted erosions. The
clinical manifestations of the disorder often vary with
age. In infancy the eczematous lesion usually appear
on the cheeks and scalp (Fig. 46-13). The skin of the
cheeks may be paler, with extra creases under the eyes,
called
Dennie-Morgan folds
. During childhood, lesions
involve flexures in the nape of the neck, and the dorsal
aspects of the limbs.
Adolescents and adults usually have dry, red patches
affecting the face, neck, and upper trunk. The bends of
the elbows and knees are usually involved. In chronic
cases, the skin is dry, leathery, and lichenified. Persons
with dark skin may have a papular eruption and poorly
demarcated hypopigmentation patches on the cheeks
and extremities. In persons with black skin, pigmen-
tation may be lost from lichenified skin. Acute flares
may present with red patches that are weepy, shiny, or
lichenified, and with plaques and papules. Itching may
be severe and prolonged with both childhood and adult
forms of atopic dermatitis. Secondary infections are
common.
Treatment is designed to target the underlying
abnormalities: dryness, pruritus, infection, and inflam-
mation.
29
Basic therapy begins with optimal skin care,
addressing the skin barrier defect with continuous use
of emollients and skin hydration, along with avoiding
exposure to irritants such as wool clothing, soaps, and
hot water.
Topical corticosteroids remain an important treat-
ment for acute flare-ups but can cause local and sys-
temic side effects. Potency of topical corticosteroids is
classified by the potential for vasoconstriction. In gen-
eral, only preparations that have weak or moderate
potency are used on the face and genital areas, whereas
those that have moderate or high potency are used on
other areas of the body. Lower-potency corticosteroids
may be sufficient on all areas of the body in younger
children. One of the main concerns of topical corticoste-
roid use is skin thinning. Another concern is secondary
adrenal suppression and the suppression of growth in
children resulting from systemic absorption. Wet-wrap
therapy, in which a wet dressing is applied over emol-
lients in combination with topical antiseptics or topical
corticosteroids, has been shown to be beneficial in some
cases of severe atopic dermatitis. Elimination of aller-
gens in the living environment is a hallmark of therapy.
Systemic or adjuvant therapy is usually reserved
for severe acute exacerbations. Short-term corticoste-
roids are also used during acute flare-ups in adults.
Antihistamines may be used to relieve itching. Secondary
infection with
S. aureus
is common and may be treated
with systemic antimicrobial therapy. Phototherapy can
be an important adjunct for severely affected adults and
adolescents older than 12 years of age.
Urticaria
Urticaria, or hives, is a common skin disorder character-
ized by the development of edematous wheals accompa-
nied by intense itching.
30,31
The lesions typically appear
as raised pink or red areas surrounded by a paler halo
(Fig. 46-14). They blanch with pressure and vary in size
from a few millimeters to centimeters. Angioedema,
which can occur alone or with urticaria, is character-
ized by nonpitting, nonpruritic, well-defined edematous
swelling that involves subcutaneous tissues of the face,
hands, feet, or genitals. It is more likely than urticaria
to produce life-threatening swelling of the tongue and
upper airways.
Urticaria can be acute or chronic and due to known or
unknown causes. Numerous factors, both immunologic
FIGURE 46-13.
Atopic dermatitis.The cheeks are a typical
location in an infant. (From Goodheart HP. Goodheart’s
Photoguide to Common Skin Disorders. Philadelphia, PA:
Wolters Kluwer Health | Lippincott Williams &Wilkins; 2009:52.)
FIGURE 46-14.
Urticarial drug eruption. Note the bizarre
shapes of the urticarial plaques. (From Goodheart HP.
Goodheart’s Photoguide to Common Skin Disorders.
Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams &
Wilkins; 2009:298.)
