why is it when one person is subjected to a type 4 immunological
reaction they only develop hives, while another person goes into
anaphyletic shock?

Hello, 

There are four categories of immunologic reactions.  These are:

Type I - anaphylactic reaction - 
    Caused by the binding of preformed IgE antibodies to the foreign
antigen.  The preformed antibodies are formed after the first exposure
and cause the anaphlyactic reaction upon subsequent exposure.

Type II - cytotoxic -
     Caused by IgG and IgM antibodies - this is the principle type of
reaction seen in autoimmunity

Type III - immune complex -
     Caused by aggregates of antibodies lodging in small capillary
beds where neutrophils and other cytotoxic cells become activated and
cause damage.  Seen most commonly in nephritic syndroms in the kidney.

Type IV - delayed-type hypersensitivity -
     Mediated by T-cells, this type of reaction is most typified by
the tuberculin skin test.  Antigen is bound and causes a local
infiltration (hives"


So, in an overall fashion, the answer to your question is that the
difference between just having "hives" and having an anyphylactic
reaction is the presence of preformed IgE antibodies in the person
with the anaphylactic reaction.

A short overview of the types of immunologic reactions (at the very
bottom):
http://www.uta.edu/biology/simecka/classnotes/3312/Immunology_review.htm

Another short immunology review that details the roles of various
immune cells in inflammation:
http://www.austincc.edu/kotrla/BB%203%20Immunology.PDF

A veterinary site with pictures of immune reactions:
http://www.vetmed.ufl.edu/path/teach/vem5110b/hi/hi.htm


Please let me know if you have further questions.

synarchy

Google search:
type iv immunologic reaction
delayed-type hypersensitivity
immunology review

Hives and Anaphylactic Shock are varying degrees of allergic reactions
both caused by the production of histamines in your body in response
to allergens.  Histamines lower your blood pressure which could result
(in some people) in shock.  Anaphylaxis means a severe or systemic
allergic reaction, the shock is caused by the natural consequence of
the histamines lowering blood pressure to a dangerous level.  But
please...never say "just hives", my Epipen stands ready anytime my
hives start getting the size of dinner plates, my tongue swells to the
point that my breathing becomes labored and my eyes swell shut. (I
have hypertension so I have been fortunate that the lowering of my
blood pressure due to significant histamine production has not caused
me to go into shock...yet.)

I need to know why does one get hives while the other goes into shock.
I am not following your answer. Can you please help me clarify the
difference. Thanks so much..