LEUKORRHOEA
LIFE EXPECTANCY
The
patches
are
usually
harmless,
although occasionally they result in a
cancerous change in the affected tissue.
If the condition persists, the patches
are removed under local
anaesthesia
and tissue is examined microscopically
for signs of malignant change. (See also
mouth cancer; vulva, cancer
of.)
leukorrhoea
See
vaginal discharge.
leukotriene receptor antagonists
A
group of
antiallergy drugs
, such as
mon-
telukast
and zafirlukast, used to prevent
symptoms of mild to moderate
asthma.
The drugs work by blocking the effects
of leukotrienes - naturally occurring sub-
stances released in the lungs during an
allergic reaction.
Because they are not
bronchodilator
drugs
, and will not relieve an existing
attack, they are usually used with bron-
chodilators and inhaled
corticosteroids
to reduce the frequency of attacks.
Side effects include gastrointestinal
disturbances and headache. Skin and
hypersensitivity reactions may also occur.
levamisole
An
anthelmintic drug
given
by mouth in a single dose to eliminate
roundworm
infestation. Side effects of
levamisole are rare but can include mild
nausea or vomiting.
levodopa
A drug used to treat
Parkin-
son's disease.
Side effects include nausea,
vomiting, nervousness, and agitation.
levonorgestrel
A
progestogen drug
used
in some
oral contraceptives.
levothyroxine
A synthetic version of
the
thyroid hormone
thyroxine, used to
treat
hypothyroidism
. Side effects, such
as rapid heartbeat and tremor, may occur
if the initial dose is too high.
LH
The abbreviation for
luteinizing hor-
mone
.
LH-RH
The abbreviation for
luteinizing
hormone-releasing hormone
.
libido
Sexual desire. Loss of libido is a
symptom of many physical illnesses and
of
depression
,
drug abuse
, and
alcohol
abuse. (See also
sexual desire, inhibited.)
lice
Small, wingless insects that feed
on human blood. There are 3 species:
pediculus humanus capitis
(the head
louse),
PEDICULUS HUMANUS CORPORIS
(the
body louse), and
phthirus pubis
(the crab,
or pubic, louse). All have flattened bod-
ies and measure up to 3 mm across.
Head lice live on the scalp and their
bite causes intense itching. They are
spread by direct contact. Their tiny eggs
(nits) attach to hairs close to the scalp.
Body lice live and lay eggs on clothing
next to the skin. They can transmit epi-
demic
typhus
and
relapsing fever
.
Crab
lice live in pubic hair or, more rarely, in
armpits, beards, or eyelashes; they are
usually transmitted during sexual contact
(see
pubic lice
).
Various preparations
can be applied to kill lice and eggs.
lichenification
Thickening and harden-
ing of the
skin
caused by repeated
scratching, often to relieve the intense
itching of disorders such as
atopic
eczema
or
lichen simplex
.
lichen planus
A common
skin
disease
of unknown cause that usually affects
middle-aged people. Small, shiny, in-
tensely itchy, pink or purple raised spots
appear on the skin of the wrists, fore-
arms, or lower legs. There is often a lacy
network of white spots covering the
inside lining of the cheeks. The disease
is treated with topical
steroid drugs
.
lichen
sclerosus
et
atrophicus
A
chronic skin condition of the anogenital
area. The skin is scarred and white, and
the anatomy of areas such as the vagi-
nal opening or the foreskin may become
distorted. Treatment is with potent top-
ical
steroid drugs
.
lichen simplex
Patches of thickened,
itchy, sometimes discoloured skin, due
to repeated scratching. Typical sites are
the neck, wrist, elbow area, and ankles.
Lichen simplex is most common in
women and is often
stress
-related. Treat-
ment is with oral
antihistamine drugs
and
creams containing
corticosteroid drugs,
and may also involve addressing any
underlying stress or anxiety.
lid lag
A momentary delay in the nor-
mal downward movement of the upper
eyelids that occurs when the eye looks
down. Lid lag is a characteristic feature
of
thyrotoxicosis
, and usually occurs in
conjunction with
exophthalmos
.
lidocaine
A local anaesthetic (see
an-
aesthesia, local
) used to numb tissues
before minor surgical procedures, and
as a
nerve block
.
life expectancy
The number of years a
person can expect to live. Life expectancy
339
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