Itchiness overview and Definition

Itchy skin is also called as pruritus is an irritating and uncontrollable sensation that makes the person to scratch to relieve the feeling. The possible causes of itchiness includes the illness and skin conditions. It is also otherwise called as pruritus.

It’s important to see a doctor for itchiness if the cause isn’t obvious. They can find the underlying cause and provide treatments for relief.

Several home remedies such as over-the-counter creams and moisturizers work well for itching


The main cause is the hyperactivation of the sympathetic nervous system causing extreme vasoconstriction of the peripheral blood vessels leads to hypoxia.

The rashes and allergic reactions to the following reactions:

This includes the type 2 allergic reactions.

In this reaction humoral antibodies and complement system(a type if immune response) comes into the role.This reaction results in lysis of target cells.Cells take part in this reaction include  tissue macrophages,platelets,natural killer cells ,neutrophils and eosinophils and amin antibodies taking place in this reaction include IgG and IgM.This reaction appears after 15-30 minutes after the exposure.

The immune system of the body mainly focus on the body’s two subsets of T-lymphocytes, known as T helper cells TH1 and TH2. In the normal immune response, TH1 cells releases the mediators which aids the body to defend against invasion from parasites, bacteria and viruses.

Activators of these nerves include histamine, neuropeptide substance P, [1] serotonin, bradykinin, proteases (eg, mast cell tryptase), and endothelin (which stimulates the release of nitric oxide). Impulses are transmitted from the dorsal root ganglion to the spinothalamic tract and eventually to the thalamus.

In allergic individuals, TH2 cells and their mediators encourage the immune system to recognise allergens as an invader, and produce a response against the foreign bodies.Some states that the people living in sterile environment free of exposure to antigen develops reduced immune response to fight against them.

For an allergy to take place,the allergen must be come into contact with the body.. Antigen-presenting CELLS SUCH as the macrophages and dentritic cells which are present in the mucosal surface of the cells sensitize the antigen.. Allergen enters into the immune system in many ways such as through inhalation,through skin contact, and antigen presenting cells sensitize these allergens and provoke an immune response and this allergen is processed and displayed on the surface of the antigen presenting cells. These cells then migrate to the T lymphocytes and presents the antigen to them which in turn activates B cells to secerete IgE antibodies. This IgE antibodies which is specific to the allergen comes into contact with mast cells on the mucosal surface and basophils on the blood.

After the period of sensitisation described above there is a period of latency, and on subsequent re-exposure to the allergen the allergic response is triggered: allergen cross-links with the IgE on the surfaces of the mast cell or basophil, causing the cell to ‘degranulate’ or release inflammatory mediators. These include largely histamine and other mediators, including cysteinyl leukotrienes, prostaglandins and kinins. They have different actions in terms of symptoms in different organs.

Differential Diagnosis


           Several markings are made on the patient skin and each mark should be 2 cm apart.

         Allergic solution is taken.

          A drop is placed on the skin and the prick is made with the lancet and the reactions happens within 15-20 mints and the results are checked and graded accordingly.

 Intradermal skin test

It is similar to skin test in which the the small amount of allergen is injected into the skin.This test is done if the prick test is negative.

Challenge test

This test is done in food allergy cases.The patient is asked to consume small amount of the allergen and the effects are supervised under healthcare proffesional

Blood test

In this test, a sample of your blood is drawn. This test is also called serum IgE testing or ImmunoCAP test.InnumoCAP test is based in the fluoro Immunoassay and complement system.It is used to measure the amount of antibodies produced in response.

Patch test

This test involves placing a small amount of possible allergens on your skin (usually your back) and then covering each of them with a bandage. Your allergist may perform this test if they suspect an allergy in which the allergic reaction is delayed. The bandages are left in place for two to three days before you return to the office to have the bandages removed and your skin examined.

Component-Resolved Diagnostic Tests or Molecular-Based Diagnosis:

        This test is done in food allergy patients to patients to obtain what type of proteins they are allergic to it.

Mast cell Tryptase Levels Assessment:

      The serum level of  β-tryptase  can be used to assess anaphylaxis and mast cell activation.


Avoid items that causes dryness to the skin

Apply moisturizer

Avoid scratching

Reduces the stress or anxiety