kala-azar A form of leishmaniasisthat
is spread by insects. Kala-azar occurs
in parts of Africa, India, the Mediter-
ranean, and South America.
kaolinAn aluminiumcompound used
as an ingredient in some antidiarrhoeal
drugs.Kaolin is taken orally and in-
creases the bulk of faeces. It is also
believed to adsorb bacteria,viruses, and
toxins in the intestine, transporting
them through the digestive tract for
excretion in the faeces.
Kaposi’s sarcomaA cancerous tumour
arising from blood vessels, usually in
the skin. Kaposi’s sarcoma usually only
occurs in those people who have AIDS.
The tumours, which consist of pinkish-
brown raised areas or flat patches, can
spread rapidly. They usually start on the
feet and ankles, spread up the legs, and
then appear on the hands and arms.
Tumours can also affect the gastroin-
testinal and respiratory tracts, where they
may cause severe internal bleeding. Skin
lesions may be treated with radiotherapy.
Anticancer drugsmay be used for wide-
spread skin disease or internal lesions.
karyotypeThe characteristics of chro-
mosomes, in terms of number, size, and
structure, in an individual or a species.
The term “karyotype” is also applied to a
diagram of chromosome pairs arranged
in their assigned numerical order.
Kawasaki diseaseA rare acute illness
of unknown cause that most commonly
affects children under 2. The disease is
characterized by fever lasting 1–2 weeks,
conjunctivitis, dryness and cracking of
the lips, swollen lymph nodesin the neck,
reddening of the palms and soles, and a
generalized rash. By the end of the 2nd
week of illness, the skin at the tips of
the fingers and toes peels and other
symptoms subside. The heart muscle
and coronary arteriesare affected in
about 1 in 5 cases. High dose gamma-
globulinand aspirinmay be given to
prevent associated heart complications.
Most children recover completely.
keloidA raised, hard, irregularly shaped,
itchy scar on the skin due to a defective
healing process in which too much colla-
genis produced, usually after a skin
injury. Keloids can develop anywhere on
the body, but the breastbone and shoul-
der are common sites. Black people are
affected more than whites. After several
months, most keloids flatten and cease
to itch. Injection of corticosteroid drugs
into the keloid may reduce itchiness
more quickly and cause some shrinkage.
keratinA fibrous proteinthat is the
main constituent of the tough outer-
most layer of the skin,nails, andhair.
keratitisInflammation of the cornea. It
often takes the form of a corneal ulcer
and may result from injury, contact with
chemicals, or an infection. Symptoms of
keratitis include pain and excessive
watering of the eye, blurring of vision,
and photophobia. Noninfective keratitis
is treated by covering the affected eye.
Drugs such as antibioticsmay be given
to treat infective keratitis.
keratoacanthomaA type of harmless
skin nodule that commonly occurs in
elderly people, most often on the face
or arm. The cause is unknown, but many
years of exposure to strong sunlight or
long-term use of immunosuppressant
drugsmay be factors. Initially, the nod-
ule resembles a small wart, but it grows
to 1–2cm across in about 8 weeks.
Although the nodule usually disappears
gradually after this, surgical removal is
often recommended to prevent scarring.KALA–AZAR KERATOACANTHOMA
K
KAPOSI’S SARCOMAK
Flat sarcoma Raised sarcoma