C h a p t e r 4 6
Disorders of Skin Integrity and Function
1157
(Bactroban), which has few side effects, may be
effective for limited infections. If the area is large or if
there is concern about complications, systemic antibiot-
ics are used.
Another form of impetigo exists,
bullous impetigo,
which is usually caused by
Staphylococcus aureus
.
10
Bullous impetigo is more common among children
and occurs intermittently, with some cases transmitted
among family members, but most often found among
the institutionalized. Thin bullae erupt that appear
clear to cloudy and coalesce. The bullae open, leaving
the original bullous rim with central thin, flat, honey-
colored crusts, or in some cases denuded areas. The
face is often affected, but bullous impetigo may occur
anywhere on the body. The treatment measures are the
same as for nonbullous impetigo.
Cellulitis.
Cellulitis is a deeper infection affecting the
dermis and subcutaneous tissues.
11
It is usually caused
by group A
β
-hemolytic streptococci or
S. aureus,
but
can be caused by bacteria specific to certain activities,
such as fish handling, swimming in fresh or salt water,
or from animal bites or scratches. Preexisting wounds
(e.g., ulcers, erosions) and tinea pedis are often portals
of entry. Legs are the most common sites, followed by
the hands and pinnae of the ears, but cellulitis may occur
on many body sites. The lesion consists of an expanding
red, swollen, tender plaque with an indefinite border,
covering a variety of widths (Fig. 46-7). Cellulitis is fre-
quently accompanied by fever, erythema, heat, edema,
and pain. Cellulitis often involves the lymph system and,
once compromised, repeat infections may impair lym-
phatic drainage, leading to chronically swollen legs, and
eventually dermal fibrosis and lymphedema. Incorrectly
treated, it may result in septicemia, nephritis, or death.
Treatment measures (oral and intravenous antibiotics)
are aimed at the invasive organisms and the extent of
the infection.
Viral Infections
Viruses are intracellular pathogens that rely on live cells
of the host for reproduction. They have no organized
cell structure but consist of a deoxyribonucleic acid
(DNA) or ribonucleic acid (RNA) core surrounded by a
protein coat. The viruses seen in dermatoses tend to con-
tain DNA. They invade the keratinocyte, begin to repro-
duce, and cause cellular proliferation or cellular death.
The incidence of viral dermatoses is increasing. This has
been attributed to the use of corticosteroid drugs, which
have immunosuppressive properties, and the use of anti-
biotics, which alter the bacterial flora of the skin. As the
number of bacterial infections has decreased, there has
been a proportional rise in viral skin diseases.
Verrucae.
Verrucae, or warts, are common benign pap-
illomas caused by the DNA-containing human papillo-
mavirus (HPV).
12
As benign papillomas, warts represent
an exaggeration of the normal skin structures. There
is an irregular thickening of the stratum spinosum and
greatly increased thickening of the stratum corneum.
The classification of warts is based largely on morphol-
ogy and location.
Although warts vary in appearance depending on their
location, it is now recognized that the clinically distinct
types of warts result not simply because of the anatomic
sites in which they arise, but also because of the distinct
type of HPV. There are more than 80 types of HPV
found on the skin and mucous membranes of humans
that cause several different kinds of warts, including skin
warts and genital warts. Many of the HPV types that
cause genital warts are sexually transmitted, some of
which (types 6, 11, 16, and 18) may increase the risk of
cervical cancer (discussed in Chapter 41).
Nongenital warts often occur on the hands and feet.
They are commonly caused by HPV types 1, 2, 3, 4, 27,
and 57, and are not considered precancerous lesions.
They are classified as common warts, flat warts, and
plantar or palmar warts. Common warts, or verrucae
vulgaris, are the most common type. The lesions can
occur anywhere, but most frequently occur on dorsal
surfaces of the hands, especially the periungual area,
FIGURE 46-6.
The lesions on this patient’s forearm proved
to be a dermatological condition caused by Staphylococcus
aureus bacteria. Note the blister-like rash and the crusted
lesion that resulted from the golden brown discharge as it
dried. (From the Centers for Disease Control and Prevention
Public Health Image Library. No. 14927. Courtesy of Dr. Herman
Miranda, Univ. of Trujello, Peru; A. Chambers.)
FIGURE 46-7.
Cellulitis on leg infected with Staphylococcus
aureus and Pseudomonas.
