Listen from Dr. R K Joshi about the overall management protocols that are required to be followed in Acute & Chronic urticaria
Published: Feb 23, 2021 03:14:38 PM IST
Updated: Feb 26, 2021 01:06:58 PM IST
What is Urticaria?
Urticaria also known as hives is a common disorder which is characterized by the sudden onset of itchy wheals and/or angioedema. In urticarial the skin of the entire body or only a portion may be affected. The wheals may occur in response to certain stimuli (e.g. cold, pressure, or sunlight) or spontaneously.
Basically wheals have 3 characteristics
A superficial swelling of the skin of different sizes, almost always surrounded by a redness
Itching or burning
Volatility – the appearance of the skin usually returns to normal within 1-24 hours.
How Urticaria is present?
In Urticaria there are wheal formations which are lumpy, erythematous red lumps on the skin which stay only for 2-4 hours on the skin & disappear spontaneously but they do replace by new crop of these lesions so they come & go. In some patients they can be associated with deeper inflammation & reaction which is called as angioedema. When there is involvement of mucus membrane & respiratory tract that leads to severe anaphylactic reaction. This disease starts with few skin lesions to a fatality leading to respiratory choking.
Issued in Public Interest by Oaknet HealthcareAcute & Chronic Urticaria
In case of Acute urticaria hives are present for less than six weeks. Depending on the rate at which hive formation occurs and the length of time acute urticaria is divided into two general types, one type produces lesions that last 1-2 hours and is typically encountered in physically induced hives. The inciting stimulus is present only briefly, and there is prompt mast cell degranulation. Biopsy of such lesions reveals little or no cellular infiltrate. The second type produces a prominent cellular infiltrate, and individual lesions can last as long as 36 hours. This type is encountered with food or drug reactions, delayed pressure urticaria, chronic spontaneous urticaria, and urticarial vasculitis
When acute urticaria is caused due to allergy mast cells in the skin are activated, degranulate, and secrete histamine, leukotrienes, platelet activating factor (PAF), enzymes such as tryptase and chymase, cytokines, and chemotactic cytokines (chemokines).
Acute urticaria can result from "non-specific" stimulation of mast cells, when there is degranulation of mast cells in the absence of a defined allergen.
In Chronic urticaria there is occurrence of spontaneous wheals, angioedema or both for more than six weeks. It is characterized by the appearance of weals, angioedema or both longer than 6 weeks. In Chronic Urticaria, wheals consist of a swelling area of different size and shape with a larger erythema, often pruritic. Lesions usually disappear in 24 h. In vasculitis and pressure urticaria lesions persist longer. According to 2014 revised European Academy of Allergy and Clinical Immunology guideline, chronic urticaria is classified into the two subgroups chronic spontaneous urticaria and chronic inducible urticaria. Chronic spontaneous urticaria is the recurrent development of transient wheals, angioedema, or both for >6 weeks due to known or unknown causes. Infections, food intolerance, drugs and autoimmunity are the cause of chronic spontaneous urticaria.
Chronic inducible urticaria is characterized by presence of characteristic features of urticaria after triggering of specific stimulus. Chronic inducible urticaria often included dermographism, aquagenic, cholinergic, delayed pressure, solar, vibration, cold and heat urticaria
Clinical Test for Chronic Spontaneous Urticaria
Autologous Serum Skin Testing – In this test, Serum is taken from patients’ blood, serum is prepared from that blood, 0.5 ml of which is injected into the skin & if there is wheal formation it is considered as positive.
Causes of Chronic Spontaneous Urticaria
The causes of Chronic Spontaneous Urticaria include
Chronic infections (e.g., hepatitis B and C, EBV, herpes simplex, Helicobacter pylori, or parasites)
Malignancies, in particular lymphoproliferative disorders, multiple myeloma, and other gammopathies (e.g., MGUS, Schnitzler syndrome)
Investigations in Acute Urticaria
Skin allergy test
Blood test (RAAST)
Various test for Inducible or Chronic Spontaneous Urticaria
Complement C3 & C4
C1 Esterase inhibitors
Skin Biopsy – To rule out urticarial vasculitis
When urticarial lesions or wheals stay for more than 24 hours then it may be immunological cause & may be a part of lupus erythematosus. Sometimes these patients are associated with thyroiditis so thyroid antibody test needs to be done.
Treatment of urticaria which include
Histamine (H-2) blockers.
Tricyclic antidepressant help relieve itching
Asthma drugs with antihistamines
Omalizumab, a monoclonal antibody
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