2. HIVES
Hives is also known as urticaria are raised, red, itchy welts (wheals, or
swellings) of various sizes that seem to appear and disappear on your skin.
In most cases, hives are harmless and don't leave any lasting marks, even
without treatment. The most common treatment for hives is antihistamine
medications.
Signs and symptoms of hives include:
Raised, red or white welts (wheals, or swellings) of various sizes.
A single welt or group of welts that can cover large areas of skin .
Welts that resolve while new welts erupt, making it seem as if the condition
"moves" .
Burning or stinging in the affected area .
Itching, which may be severe.
Hives can be either acute or chronic. By definition, acute hives can last from
less than a day to up to six weeks, whereas chronic hives last more than six
weeks — sometimes occurring for months to years at a time.
4. causes
Hives are caused by inflammation in the skin. In some cases, hives are triggered when certain cells
(mast cells) release histamine and other chemicals into your bloodstream and skin.
Allergic reactions to medications or foods can cause acute hives. Many allergens have been identified.
Examples include:
Foods. Many foods can cause problems in sensitive people, but shellfish, fish, nuts, eggs,
chocolate and milk are frequent offenders. Food additives, such as salicylates and sulfites, are other
potential allergens.
Medications. Almost any medication may cause hives ; common culprits include penicillin, aspirin,
ibuprofen (Advil, Motrin, others) and blood pressure medications.
Other allergens. Other substances that can cause hives include direct contact with pollen, animal
dander, latex and insect stings.
Additional triggers that may produce hives include:
Physical factors. Environmental factors can result in the release of histamine with subsequent hives
in some people. Examples of these factors include heat, cold, sunlight, water, pressure on the skin,
emotional stress and exercise.
Dermatographia. The name of this condition literally means "write on the skin." When pressure is
applied to the skin or the skin is scratched, raised lines appear on those areas due to histamine-
based angioedema that leads to swelling beneath the skin.
In addition to these triggers, hives sometimes occur in response to your body's production of
antibodies. This may occur because of blood transfusions; immune system disorders, such as lupus
or cancer; certain thyroid disorders; infections, such as hepatitis; or even a cold.
5. complications
Hives can cause:
Itching
Discomfort
In more serious cases — such as when swelling occurs inside
your mouth or throat — complications can include:
Difficulty breathing
Loss of consciousness
Anaphylactic shock : Anaphylactic shock (anaphylaxis) is a
serious allergic reaction involving your heart or lungs. Your
bronchial tubes narrow, it's difficult to breathe, and your
blood pressure drops, causing dizziness and perhaps loss of
consciousness or even death. Anaphylactic shock occurs
rapidly, and requires immediate medical care
6. ANTIGEN
An antigen is any substance that
causes your immune system to
produce antibodies against it. An
antigen may be a foreign substance
from the environment such as
chemicals, bacteria, viruses, or
pollen. An antigen may also be
formed within the body, as with
bacterial toxins or tissue cells.
7. ELISA
The ELISA is a fundamental tool of
clinical immunology, and is used as
an initial screen for HIV detection.
Based on the principle of antibody-
antibody interaction, this test allows
for easy visualization of results and
can be completed without the
additional concern of radioactive
materials use.
