Allergic Reaction Investigation

As our class studies connective tissue we learned about the different types of connective tissues and their function in the human body. Loose connective tissue or areolar tissue is characterized by loose arranged fibers and many cells. These cells include leukocytes, which are able to wander and migrate from local blood vessels in response to specific stimuli. Loose connective tissue is the site of both inflammatory and immune reactions. However, in class we haven’t had the chance to investigate the mechanisms of these reactions from a clinical perspective.

            These wandering/transient white blood cells include lymphocytes, plasma cells, neutrophils, eosinophils, basophils, and monocytes. From a clinical perspective mast cells and basophils play a huge role in allergic reactions. Mast cells are connective tissue cells that are filled with basophilic granules. Mast cell activation is initiated when a person is exposed to an allergen that reacts with the IgE antibodies on the surface of mast cells. As a whole, the cascade of events are termed allergic reactions.

There are two different methods the body can react upon an allergic reaction. The first is an immediate hypersensitivity which cause symptoms such as erythema (redness in the skin), itching and swelling, and pain sensations on the skin. Symptoms such as a runny nose, sneezing, and increased mucous production are also common. These symptoms are triggered by the release of histamine and other mediators from mast cells and basophils. When the discharge of the mast cell is massive this can cause an even more drastic condition known as anaphylaxis. When a person goes into anaphylactic shock, histamine functions as a vasodilator and increases the permeability of the blood vessels. This can be life threatening because the increased vasodilation causes significant hypotension. Along with hypotension, the person may also experience difficulty breathing due to swelling in the throat. Immediate treatment with epinephrine is needed because of its function as a vasoconstrictor.

The other method the body can react is termed the late-phase allergic reaction. This happens when the symptoms of the immediate hypersensitivity reaction have been treated but symptoms re-surface six to twenty-four hours later. However, the symptoms of the late-phase allergic reaction are not as drastic as the immediate hypersensitivity reaction even though it consists some of the same symptoms. The late-phase allergic reaction is characterized by an elevated white blood cell count and the symptoms usually last a few hours and disappear in one to two days.

Epinephrine (Vasoconstrictor)

Mast cell

Basophil