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U N I T 1 3
Integumentary Function
booths continues to rise, while adherence of tanning
booths to national guidelines is often violated.
46
Clinical Features.
Sunburn is caused by excessive expo-
sure of the epidermal and dermal layers of the skin to
UV radiation, resulting in an erythematous inflamma-
tory reaction.
47
Sunburn ranges from mild to severe.
Mild sunburn consists of various degrees of skin redness.
The burn continues to develop for 24 to 72 hours, occa-
sionally followed by peeling skin in 3 to 8 days. Some
peeling and itching may continue for several weeks.
Inflammation, blistering, weakness, chills, fever, mal-
aise, and pain often accompany severe forms of sunburn.
Scaling and peeling follow any overexposure to sunlight.
Dark skin also burns and may appear grayish or gray-
black. Severe sunburns are those that cover large por-
tions of the body with blisters or are accompanied by a
high fever or intense pain.
The UV rays of sunlight or other sources can be com-
pletely or partially blocked from the skin surface by
sunscreens. There are two primary types of sunscreens
available on the market—chemical (soluble) agents and
physical (insoluble) agents.
45
Chemical agents (e.g.,
para-aminobenzoic acid [PABA] derivatives) protect
the skin from absorbing sunlight, and physical agents
(e.g., micronized titanium dioxide and microfine zinc)
work by reflecting sunlight. The
sun protection fac-
tor
(SPF) rating of the various sunscreen products is
based on their ability to obstruct UV radiation (UVR)
absorption. The ratings usually are on a scale of 1 to
30+, with the higher ratings indicating greater blocking
of UVR.
45
Products with a higher SPF screen out more
UVB rays, which are primarily responsible for acute
sun damage. Shielding the skin with protective cloth-
ing and hats or head coverings helps decrease UVR
exposure.
Mild to moderate sunburns are treated with anti-
inflammatory medications, such as aspirin or ibuprofen,
until redness and pain subside. Cold compresses, cool
baths, and applying a moisturizing cream, such as aloe,
to affected skin help treat the symptoms. Steroid and
nonsteroidal agents are used depending on the severity
of the burn. Blisters should not be broken to preserve the
protective layer of the skin, hasten the healing process,
and decrease the risk of infection. Extensive second- and
third-degree sunburns may require hospitalization and
specialized burn care techniques, as described in the sec-
tion on thermal injury.
Drug-Induced Photosensitivity
Some drugs are classified as photosensitive drugs because
they produce an exaggerated response to UVR when the
drug is taken in combinationwith sun exposure. Examples
include some of the anti-infective agents (sulfonamides,
tetracyclines, nalidixic acid), antihistamines (cyprohepta-
dine, diphenhydramine), antipsychotic agents (phenothi-
azines, haloperidol), diuretics (thiazides, acetazolamide,
amiloride), hypoglycemic agents (sulfonylureas), and
nonsteroidal anti-inflammatory drugs (phenylbutazone,
ketoprofen, naproxen).
Thermal Injury
About 450,000 people in the United States require med-
ical care for burns each year, with 40,000 requiring hos-
pitalization.
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Flame burns occur because of exposure to
direct fire. Scald burns result from hot liquids spilled or
poured on the skin surface.
The effects and complications of burns fully illustrate
the essential function that the skin performs in protect-
ing the body from the many damaging elements in the
environment while serving to maintain the constancy
of the body’s internal environment. The massive loss of
skin tissue not only predisposes to attack by microor-
ganisms that are present in the environment, but also
allows for the massive loss of body fluids, interferes
with temperature regulation, challenges the immune sys-
tem, and imposes excessive demands on the metabolic
and reparative processes that are needed to restore the
body’s interface with the environment.
Classification of Burns
Burns are typically classified according to the depth of
involvement as first-degree, second-degree, and third-
degree burns.
49,50
The depth of a burn is largely influ-
enced by the duration of exposure to the heat source
and the temperature of the heating agent.
First-degree
burns
(superficial partial-thickness burns) involve only
the outer layers of the epidermis. They are red or pink,
dry, and painful. There usually is no blister formation,
as with a mild sunburn. The skin maintains its ability
to function as a water vapor and bacterial barrier and
heals in 3 to 10 days. First-degree burns usually require
only palliative treatment, such as pain-relief measures
and adequate fluid intake. Extensive first-degree burns
on infants, the elderly, and persons who receive radia-
tion therapy for cancer may require more care.
Second-degree burns
involve both the epidermis and
dermis.
Second-degree partial-thickness burns
involve
the epidermis and various degrees of the dermis. They
are painful, moist, red, and blistered. Underneath the
blisters is weeping, bright pink or red skin that is sensi-
tive to temperature changes, air exposure, and touch.
The blisters prevent the loss of body water and superfi-
cial dermal cells. Excluding excision of large burn areas,
it is important to maintain intact blisters after injury
because they serve as a good bandage and may promote
wound healing. These burns heal in approximately 1 to
2 weeks.
Second-degree full-thickness burns
involve the entire
epidermis and dermis. Structures that originate in the
subcutaneous layer, such as hair follicles and sweat
glands, remain intact. These burns can be very painful
because the pain sensors remain intact. Tactile sensation
may be absent or greatly diminished in the areas of deep-
est destruction. These burns appear as mottled pink, red,
or waxy white areas with blisters and edema. The blis-
ters resemble flat, dry tissue paper, rather than the bul-
lous blisters seen with superficial partial-thickness injury.
After healing in approximately 1 month, these burns
maintain their softness and elasticity, but there may be
the loss of some sensation. Scar formation is common.
