Atopic dermatitis A chronic condition also
called eczema, atopic dermatitis typically first
appears in infancy or early childhood and often
persists, in periods of exacerbation and REMISSION,
throughout life. Symptoms include areas of red,
cracked, weepy (oozing) sorelike eruptions that
eventually crust, scale, and thicken. Itching is
intense. The most frequent areas of involvement
are the surfaces on the inner (antecubital) surface
of the elbows and the back (popliteal) surface of
the knees, though atopic dermatitis can affect any
part of the body. Atopic dermatitis seems to have a
hereditary component, as it runs in families, and is
more common in people who have hypersensitiv-
ity conditions such as ALLERGIC RHINITIS.
People who have, or who have ever
had, atopic dermatitis should not
receive vaccination against SMALLPOX
that uses the vaccinia virus (the vaccine
administered by health-care providers
in the United States). This vaccine can
cause a particularly serious eruption of
atopic dermatitis.Treatments for atopic dermatitis outbreaks
include topical skin lubricants, such as ointments
and lotions that help the skin retain moisture, and
topical CORTICOSTEROID MEDICATIONS. The dermatolo-
gist may prescribe a course of oral corticosteroid
medication (such as prednisone) for severe or
resistant symptoms. Oral ANTIHISTAMINE MEDICATIONS
may help control itching. Scratching excoriates
the lesions, setting the stage for bacterial infection,
which then requires ANTIBIOTIC MEDICATIONS.
Atopic dermatitis outbreaks vary in severity and
length. Atopic dermatitis abates in some children as
they reach ADOLESCENCEor early adulthood, though
dermatologists believe the condition goes into an
extended state of remission rather than disappears.
In some adults, the only indications that atopic der-
matitis persists are fissures and cracks in the skin on
the palms of the hands and the soles of the feet,
which may appear to be exceedingly dry skin rather
than dermatitis. Coating the palms and soles with
petroleum jelly at bedtime, protecting the coating
with mittens and socks, often helps heal the fis-
sures. About 10 percent of the American popula-
tion has atopic dermatitis.
Contact dermatitis Numerous environmental
substances, from plant resins (poison ivy) to met-
als (nickel, stainless steel) to bath soaps and laun-
dry detergents, can irritate and inflame the skin.
Contact dermatitis may represent an allergic
response in which the IMMUNE SYSTEM, particularly
the Langerhans cells located in the dermis, overre-
acts to a substance. Allergic contact dermatitis
generally appears within 24 hours of contact,
while weeks or even months of exposure to irri-
tants may take place before causing contact der-
matitis. The location of the first point of outbreak
often helps narrow the field for identifying the
cause.
Treatment is twofold: removing the offending
irritant or ALLERGEN, and treating the symptoms.
Oral antihistamine medications and topical corti-
costeroids typically reduce itching and inflamma-
tion. It may take up to three months for all
symptoms of contact dermatitis to resolve. Contact
dermatitis can be a matter of OCCUPATIONAL HEALTH
AND SAFETYwhen the offending substance is neces-
sary in the workplace. People who work with
glues, paints, metals, plastics, latex rubber, and
numerous industrial chemicals commonly develop
contact dermatitis.
Exfoliative dermatitisAn uncommon but seri-
ous form of dermatitis in which the epidermis
(outer layer of the skin) becomes inflamed and
forms scales that peel away, exfoliative dermatitis
nearly always indicates systemic disease, frequently
a cancer such as LEUKEMIA, cutaneous T-cell lym-
phoma (CTCC), or LYMPHOMA. Exfoliative dermatitis
may be the earliest sign of PROSTATE CANCER, THYROID
CANCER, and COLORECTAL CANCER. It also develops in
people who have AIDS, and may occur as an
ADVERSE REACTIONto numerous medications.
Exfoliative dermatitis begins with patches of
skin (lesions) that turn red and itch. Within two
weeks the lesions spread to cover nearly the entire
surface of the skin except the soles of the feet,
palms of the hands, and face (though usually
spare the mucous membranes). The scaling and
dilation of blood vessels that follow significantly
impairs all dermal functions from IMMUNE RESPONSE
to thermal regulation (heat loss). Fluid oozes con-
tinually from the exposed dermis and the BLOOD
vessels are dilated, causing excessive cooling that
easily becomes HYPOTHERMIA. Damage to the pro-150 The Integumentary System