Cytokines are small proteins that can either step-up or
step-down the immune response. One of the cytokines,
interleukin 4 (IL4), is essential for the production of
IgE. Interleukin 5 (IL5) and others are important in
attracting other cells, particularly eosinophils, which
then promote inflammation. This spectrum of cytokines is
also released by the TH2 lymphocytes, thus further
promoting allergic inflammation.
We have seen how the first encounter with ragweed
pollen sensitizes the body with the help of lymphocytes
and results in the IgE coating of the mast cells and
basophils. Subsequent exposure results in the immediate
release of the chemical mediators that cause the various
symptoms of allergy. This process is the "early phase" of
the allergic reaction. It can occur within seconds or
minutes of exposure to an allergen. This is also known as
an immediate hypersensitivity reaction, which in this case
is to the ragweed pollen allergen.
In the context of allergy, hypersensitivity refers to a
condition in a previously exposed person in which tissue
inflammation results from an immune reaction upon re-
exposure to an allergen sensitizer.
About 50% of the time, the allergic reaction progresses
into a "late phase." This "late phase" occurs about 4 to 6
hours after the exposure. In the late phase reaction,
tissues become red and swollen due to the arrival of other
cells to the area, including the eosinophils, neutrophils,
and lymphocytes. Cytokines that are released by the mast
cells and basophils act as tiny messengers to call these
other cells to the area of inflammation. Additional
cytokines are released by the TH2 lymphocytes and they
attract even more of these cells of inflammation.
The eosinophils appear to be particularly troublesome
cells of inflammation. Eosinophils evolved to defend the
body against parasites, much like IgE. Nevertheless, they
are often present in great numbers in the blood of people
with allergies. When they arrive at the site of the
allergic reaction, they release chemicals that cause damage
to the tissues and continue to promote the inflammation.
Repeated episodes of this "late phase" reaction contribute
to chronic allergic symptoms and make the tissues even more
sensitive to subsequent exposure!
An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in people who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock.
Anaphylaxis is a serious allergic reaction that affects a number of different areas of the body at one time, and can be fatal. Causes of anaphylaxis can be food allergy, latex allergy, allergy to insect or but stings/bites, asthma, or other materials or conditions. Symptoms include flushing, itching, hives, anxiety, rapid or irregular pulse. Severe symptoms may be throat and tongue swelling, swallowing, and difficulty breathing. Some disorders appear similar to anaphylaxis such as fainting, panic attacks, blood clots in the lungs, heart attacks, and septic shock. If you think that you may be having an anaphylactic reaction, seek emergency care or call 911 immedately.
Hoarseness (abnormal deep, harsh, raspy voice) is caused by a variety of conditions in which the larynx (voice box and vocal chords) are irritated or injured. Examples of causes of hoarseness include: laryngitis, straining the vocal cords by yelling or screaming, infections, GERD, allergies, and more. Treatment of hoarseness depends on the cause.
Hay fever (allergic rhinitis) is an irritation of the nose caused by pollen and is associated with the following allergic symptoms: nasal congestion, runny nose, sneezing, eye and nose itching, and tearing eyes. Avoidance of known allergens is the recommended treatment, but if this is not possible, antihistamines, decongestants, and nasal sprays may help alleviate symptoms.
Bees, wasps, and fire ants are related insects that belong to the Hymenoptera order. There are thousands of species of wasps found throughout the world. Common wasps are yellow jackets and hornets. Types of bees include honey bees, the Africanized honey bee (killer bee), and the bumble bee. There are four types of reactions to a bee or wasp sting; 1) local reaction, 2) systemic allergic reaction, 3) toxic reaction, and 4) delayed reaction. Individuals who have a systemic or toxic reaction generally require immediate medical treatment to prevent anaphylactic reaction, and possibly death.
Biologic rhythms, or biorhythms, are how our bodies respond to the regular phases of the sun, moon, and seasons. A medical chronobiologist studies how the "body clock" or biorhythms affect diseases and how the body clock responds to treatment of diseases and conditions at different times of the day.
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