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Urticaria by Mind Map: Urticaria

1. Types

1.1. Acute

1.1.1. <6wks

1.1.2. 20% of population

1.1.3. Ax Food Drug Infections Viral illness Mycoplasma Bacterial Parasites contact Latex Food Insect

1.1.4. Prognosis 30%--->chronic urticaria

1.2. Chronic

1.2.1. >6wks

1.2.2. 1% of population

1.2.3. 40% a/w angioedema

1.2.4. Prognosis 50% will resolve w/in 1 year 20% will persist >10 years

1.2.5. Etiology Idiopathic in 80% a/w autoantibodies 20% physical urticaria Autoimmune 2/2 Vasculitis urticaria

2. Physical Urticaria

2.1. Dermatographism

2.1.1. The most common

2.1.2. Less pruritic

2.1.3. Linear rash after striking the skin with tongue depressor and may last for 30 mins

2.1.4. Types Simple The most common Dermatographea Less pruritic Symptomatic dermatographism Very pruritic Occur in pressure area Red, white or follicular dermatographism

2.1.5. Pathogenesis Serum transferred Maybe baseline elevation of histamine

2.1.6. A/W Mastocytosis Solar Urticaria Abx use Stress

2.2. Cholinergic

2.2.1. Characteristics Small hives 1-3mm w/ surrounding erythema (like SPT)

2.2.2. Trigger Passive heating Hot shower Active heating Exercise Sweating Anxiety

2.2.3. Severity Mild to life threatening

2.2.4. Provocative testing Exercise Hot water emersion (41C) bring up the body temperature by 0.7C Methacholine intracutaneous testing 0.01mg/1ml methacholine + 0.1ml of normal saline But negative predictive value of these are unknown

2.2.5. 3 different pathophysiological mechanism Sensitivity to autologus sweat Antibody mediated Direct degranulation of basophils Exaggerated cutaneous response to acetylcholine Neurogenic reflex Altered central perception of temperature changes

2.2.6. May have extracutenous manifestations Salivation Lacrimation Bronchospasm Diarrhea

2.2.7. Rx Atarax (hydrozyxin) It has anticholinergic effect

2.3. Cold induce

2.3.1. Ax Primary Aquired Familial Secondary Infections Vasculitis Cold dependent immunoglobulin diseases Localized cold urticaria two types It is imp to differentiate it from familial cold autoinflammatory syndrome It is part of the cryopyroin associated periodic syndrome Non urticarial rash

2.3.2. Dx by ice cube test placed for 10 mins -ve ice cube test in] systemic cold urticaria Cold induce cholenergic urticaria Cold dependent dermatographism FCAS PLAID (phospholipase Cγ2-Associated Antibody Deficiency and Immune Dysregulation)

2.3.3. Rx If angioedema (mucosal membrane), epipen, swimming in public places. Avoid submersion of the body above waist line.

2.4. Aquagenic

2.4.1. extremely rare reported on 50 people

2.4.2. Pinpoint hives (similar to cholinergic, 1-3mm)

2.4.3. independent of water temperature

2.4.4. Dx placing wet compress such as wash cloth at 35C on the upper body for 15-30 min

2.4.5. May have systemic symptoms headache Respiratory symptoms

2.5. Solar

2.5.1. w/in min of sun exposure

2.5.2. Dx Exposure to different wave lengths

2.5.3. DDx Phototoxic & photo allergic drug eruptions polymorphous light eruption Delay hypersensitivity reaction Component of the skin gets alter with exposure to ultraviolate radiation The most common photodermatosis Lack of systemic symptoms Rash is itchy and painful CTD

2.5.4. UVA might be effective Thickening the skin

2.5.5. Chromophore Substance that are circulated in the blood that got activated by light and sIgE will bind to it

2.6. 6) Vibratory

2.6.1. Dx Vortex mixer

2.7. 7) Delayed Pressure

2.7.1. typically developed 6-8hrs later can be 24hrs rarely within 1hrs

2.7.2. Pathology is different than other CU inflammatory cells predominant (neutrophils & eosinophil) instead of mast cell. May a/w inc IL-6 and TNF low grade fever Malaise

2.7.3. Less reposnsive to anti-histamines--Make sense! Rx. Singulair and steroid

2.7.4. Dx. suspend 15ibs weight over pt shoulder for 10-15min positive response

2.8. 8) Localized heat urticaria

2.8.1. Apply tube with that contain hot water (45C) to arm for 5 minutes

3. Serum transfer

3.1. Passive transfer by serum

3.1.1. Cold IgG, IgM, IgE or cryoglobulin

3.1.2. Dermatographism IgE

3.1.3. Solar Type 1 or Type 4 allergic reaction

4. Physical exam

4.1. Urticarial vasculitis

4.1.1. Last >24hrs

4.1.2. Painful not itchy

4.1.3. Hyperpigmentation

4.1.4. Surrounding petechia

4.2. Dermatographism

4.3. Thyroid for dysregulation

4.4. LAP and liver

4.4.1. for CLL and hepatitis (HBV & HCV) A/W cryoglobulinemia-->cold induce urticaria and urticarial vasculitis

4.5. if hyper pigmented lesion

4.5.1. Strike the skin to demonstrate if darier sign present-->cutaneous mastocytosis-->send baseline tryptase

5. Rx.

5.1. Counselling

5.1.1. Not serious yet troblesome

5.2. drugs

5.2.1. Second generation H1 blockers Cetrizine (Reactin) 10mg OD-->BID-->20mgBID Levocetrizine(Xyzal) dosing 5-->10-->20mg QHS Desoloratadine (Aerius) Same dosing as levocitrizine Loratadine (Claritin) Fexofenadine (allegra) 20/60/120/240mg BID

5.2.2. Increase dose of 2nd gen to X4 the regular dose

5.2.3. Leukotriene antagonist Montelukast Zafirolukast

5.2.4. Doxepine TCA with H1 and H2 blocking activity

5.3. Avoid

5.3.1. NSAIDs

5.4. Third line (last resort)

5.4.1. Colchicine

5.4.2. Sulphasalazine

5.4.3. Dapson

6. Definiation:

6.1. Urticaria

6.1.1. Raised

6.1.2. Pruritic

6.1.3. Erythematous

6.1.4. Transient <24hrs in same spot

7. Pathophysiology

7.1. Early phase

7.1.1. Vasoactive mediators Immediate Histamine Membrane phospholipids Leukotrienes Prtostaglandins

7.1.2. Vasodilatation

7.1.3. In urticaria superficial dermis

7.1.4. In angioedema deep dermis

7.2. Late phase

7.2.1. 4-8hrs

7.2.2. Cytokines TNF-a IL-4 Th2 Switch to IgE IL-5 Eosinophillic recruiter IgA switching in the gut

7.2.3. Inflammatory cells Acute urticaria Rare infiltrate Chronic Urticaria Perivascular So pathology is different between the two! yet biopsy is rarely needed.

7.3. CSU (chronic sponteous urticaria)

7.3.1. You may see basopenia

7.3.2. Two types of basophils IgE responser Non-IgE responser

8. Investigations

8.1. Acute Urticaria

8.1.1. Skin test +/- sIgE based on hx.

8.2. Chronic urticaria

8.2.1. In unremarkable hx and px Consider CBC/diff/ESR/CRP/LFT/TSH

8.2.2. Not routinely recommended anti-thyroid antibodies Anti-FcRa or anti-IgE Fc Skin test for food, inhalants etc..

8.2.3. Case by case biopsy if suspected vasculitis C1 estrase assay if isolated angioedema, C4 Cryglobulinemeia HCV Autoimmune work-up (ANA, anti-DsDNA, RF, C3,C4 etc..)