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Hives (Urticaria)

by Carlo Raj, MD

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    00:03 Let's talk about Urticaria (Hives).

    00:06 So what urticaria (hives), what does this mean to you? The IgE-mediated.

    00:10 As soon as you hear IgE-mediated what does that mean to you? It means that now you've been exposed to a particular antigen, in which you have now elicited a Type 1 hypersensitivity.

    00:20 Isotype switching, IgE then lands upon your IgE receptors of the mast cell.

    00:25 And what did you release? Ah, histamine. Histamine, histamine.

    00:30 Histamine has what can effect on your blood vessels? Vasodilation. Good.

    00:36 Welcome to Hives.

    00:38 Now once you have vasodilation taking place with the histamine being released by the mast cell You have an area that appears what? Maybe a little edematous.

    00:50 Erythematous caused by food, medication, exercise, temperature, vibration, stress.

    00:56 Those things that you can expect in which hives are going to develop.

    01:00 And two to three episodes per week, for six weeks is a chronic urticaria.

    01:06 Be familiar to define, or how to define chronic urticaria, which is two to three episodes per week for six weeks.

    01:14 That is extremely cumbersome.

    01:18 Morphology: Rapid development of edematous enie Edematous, why? Histamine, vasodilation, edema.

    01:27 Erythematous, wheal formation.

    01:30 There are three terms here that you want to keep in mind: urticaria, hives, and wheal formation.

    01:35 To you, it's a type 1 hypersensitivity, with vasodilation, edema, and erythema.

    01:44 These lesions evolve and dissipate rapidly within 24 hours.

    01:49 And there's every possibility that if you were to take a glass slide, for example, and apply pressure, apply pressure on this hive or wheal formation with vasodilation, press upon that wheal please W-H-E-A-L, what's going to happen? Blanching.

    02:07 Because when you press upon that wheal, the fluid edema is going to then disperse.

    02:14 So that erythema that you found upon what's known as a diascopic type of examination is then going to give you your blanch type of appearance.

    02:28 Diagnosis: Rapidly evolution, clinically distinctive, and biopsy rarely performed.

    02:35 A history is going to tell you what's going to happen.

    02:37 Take a look at the image here, high formation on the thigh and the leg of this individual.

    02:42 If swelling is deeper you then consider this to be angioedema.

    02:47 Don't memorize that.

    02:49 So at this point, we're in the skin.

    02:51 And so therefore with high formation, you have edematous formation in the epidermis.

    02:56 But over a period of time, there's every possibility that the fluid may then be escaping down deep down tissue.

    03:03 And we then refer to this being type of angioedema.

    03:07 And when this occurs on, [mumble talk] what am I doing? It's a fact that around the mucosal region, I have angioedema swelling, and therefore making it difficult for me to articulate clearly.

    03:20 There is subtle superficial edema, as noted by the widely spaced collagen bundles with mild perivascular and scant interstitial infiltrates of small lymphocytes.

    03:29 With occasionally eosinophils and mast cells are seen.

    03:33 Neutrophils are rarely seen.

    03:35 Lymphatic channel dilation may be evident.

    03:37 The age of the lesion, and type of noxious stimulus may influence the histologic characteristics.

    03:45 Management: You need to identify what's actually causing the type I hypersensitivity.

    03:50 Antihistamines obviously sedating, such as maybe diphenhydramine.

    03:55 Moderately sedating will be cetirizine and non-sedating, if at all required based on the patient's habits and behavior, Maybe you're thinking about loratadine.

    04:04 but anti-histamine, you are going after the histamine, so that you can take care of the hives.


    About the Lecture

    The lecture Hives (Urticaria) by Carlo Raj, MD is from the course Inflammatory Skin Diseases.


    Included Quiz Questions

    1. Histamine release and vasodilation
    2. IgM-induced vasodilation
    3. IgE-mediated vascoconstriction
    4. Type II hypersensitivity reaction
    5. T-cell mediated response
    1. Cetirizine
    2. Topical steroids
    3. Pharmacotherapy is not recommended without a biopsy.
    4. Methotrexate
    5. Oral steroids
    1. Acquired angioedema
    2. Chronic utricaria
    3. Hereditary angioedema
    4. Allergic contact dermatitis
    5. Simple allergic reaction

    Author of lecture Hives (Urticaria)

     Carlo Raj, MD

    Carlo Raj, MD


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