I
DERMOID CYST
is a temporary rise in thyroid hormone
levels
(
hyperthyroidism
)
lasting for a few
weeks, as damage to the thyroid gland
causes it to release its hormone stores.
This is followed by insufficient levels
(
hypothyroidism
) when the stores then
become depleted.
Aspirin
is used to treat the inflam -
mation, with a short course of the
corticosteroid drug
prednisolone
given
in more severe cases. Thyroid function
usually returns to normal once the ill-
ness has been treated.
Dercum’s disease
Also called adiposis dolorosa, a disor-
der characterized by the accumulation
of localized, symmetrical fat deposits
under the skin, mainly on the forearms
and thighs. The swellings are uncom -
fortable or painful. Other symptoms of
the disease include muscle weakness
and headaches. The disease may cause
death from heart failure. Dercum’s dis-
ease mainly affects middle-aged women
and is thought to be an autosomal
dominant
genetic disorder
.
derealization
Feeling that the world has
become
unreal. It usually occurs together with
depersonalization
and may be caused by
fatigue,
hallucinogenic drugs
,
or disor-
dered brain function.
dermabrasion
Removal of the surface layer of the skin
by high-speed sanding to improve the
appearance of scars, such as from
acne
,
or to remove tattoos.
dermatitis
Inflammation of the skin, sometimes
due to an
allergy
.
Dermatitis is the same
as
eczema,
and the terms can be used
interchangeably.
The
following
are
types of dermatitis.
SEBORRHOEIC DERMATITIS
This condition is a red, scaly, itchy rash
that develops on the face (particularly
the nose and eyebrows), scalp, chest,
and back.
It
often
develops
during
times of stress and is probably caused
by an excessive growth of yeast on the
skin.
Corticosteroid drugs
and drugs that
kill microorganisms may help.
CONTACT DERMATITIS
Contact dermatitis results from a reac-
tion to some substance that comes in
contact with the skin. Common causes
are detergents, nickel, certain plants,
and cosmetics. It may be treated with
Contact dermatitis
An allergic reaction to the metal (often nickel)
in a ring has produced a red, inflamed area of
skin around the finger.
topical corticosteroids. A patch test (see
skin tests
) may be performed in order
to identify the cause.
PHOTODERMATITIS
This form of dermatitis occurs in peo-
ple whose skin is abnormally sensitive
to light. A cluster of spots or blisters
occurs on any part of the body exposed
to the sun (see
photosensitivity
) .
dermatitis artefacta
Any self-induced damage to the skin. It
may range from scratches to extensive
mutilation that produces severe ulcers
or other lesions. W hen given a medical
examination, the affected person may
vigorously deny having any part in caus-
ing the problem. Psychiatric assessment
and treatment is required to control the
behaviour. (See also
factitious disorder
. )
dermatitis herpetiformis
A chronic skin disease in w hich clus-
ters of tiny, red, intensely itchy blisters
occur in a symmetrical pattern, most
commonly on the back, elbows, knees,
buttocks, and scalp. It usually develops
in adult life and is believed to be related
to
coeliac disease
,
a condition in w hich
the lining of the small intestine reacts
to gluten, a constituent of wheat, rye,
and some other cereals.
dermatology
The branch of medicine that is con-
cerned with the
skin
,
hair
,
and
nails
,
and their disorders.
dermatome
An area of skin that is supplied with
nerve fibres by a single spinal nerve
from the cervical, thoracic, lumbar, or
sacral regions of the spinal cord.
The entire body surface is an inter-
locking pattern of dermatomes, w hich
is sim ilar from one person to another.
Abnormal sensation in a dermatome
signifies damage to a particular nerve
root, commonly due to a
disc prolapse
(“slipped” disc).
dermatome, surgical
A surgical instrument for cutting vary-
ing thicknesses of skin for use in skin
grafting procedures.
D
dermatomyositis
A rare
autoimmune disorder
in w hich the
muscles and skin become inflamed. In
most cases the cause is unknown, but
in some instances the disease is linked
to an underlying
cancer
.
Dermatomyositis causes a skin rash
that may first appear on the bridge of
the nose and cheeks, followed by a pur-
ple discoloration on the eyelids and
sometimes a red rash over the knees,
knuckles, and elbows. Muscles become
weak,
stiff,
and painful,
particularly
those
in
the
shoulders
and
pelvis;
affected people may find that they can-
not raise their hands above their head,
or
cannot
raise
themselves
from
a
squatting
position.
Calcium
may be
deposited in the muscles, particularly
in affected children.
The diagnosis is made by medical
examinations,
blood tests
,
and
biopsy
of
muscle tissue. Treatment is with
cor-
ticosteroids
and/or
immunosuppressant
drugs
and
physiotherapy
.
In about half of
all cases, full recovery occurs after a
few years. The remainder have persis-
tent muscle weakness. In some cases,
the disease eventually affects the lungs
and other organs and may be fatal.
dermatophyte infections
A group of common fungal infections
affecting the skin, hair, and nails, also
called
tinea
or, popularly, ringworm.
dermis
The inner layer of the
skin
.
dermographism
Abnormal sensitivity of the skin to
mechanical irritation, to the extent that
firm stroking leads to the appearance of
itchy weals. The condition is a form of
urticaria
(nettle rash). It is most com-
mon in fair-skinned people who have a
tendency to allergic conditions.
dermoid cyst
A noncancerous tumour w ith a cell
structure sim ilar to that of skin. The
growth contains hairs, sweat glands,
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