Urticaria

Urticaria



Basic Information image



Definition


An acute or chronic edematous skin disorder that may be caused by immunologic or nonimmunologic mechanisms. This is a reaction pattern in the skin of horses with numerous underlying causes.



Synonym(s)


Hives



Epidemiology



Genetics and Breed Predisposition


There is a genetic predisposition to atopic dermatitis, one of many causes of urticaria.



Geography and Seasonality


May be seasonal or nonseasonal depending on causative factors



Associated Conditions and Disorders


Angioedema, atopic dermatitis, insect hypersensitivity



Clinical Presentation



Disease Forms/Subtypes




• Conventional urticaria involves wheals ranging in size from 2 mm to 5 cm in diameter. Small wheals (3–6 mm) are called papular urticaria, and large wheals (≤40 cm) are termed giant urticaria.


• Linear urticaria is characterized by linear bands of urticaria vertically along the trunk.


• Chronic urticaria is defined as urticaria lasting longer than 8 weeks.



History, Chief Complaint


Acute or chronic, persistent or recurrent wheals typically occurring on the trunk, neck, or legs



Physical Exam Findings


The wheals should pit on digital pressure and typically do not remain in the same location for more than 48 hours. They are generally nonpainful and variably pruritic. In severe cases, they may ooze serum and have overlying serous crusts.



Etiology and Pathophysiology


Urticaria results from mast cell basophil degranulation. This may be immunologic and caused by atopic dermatitis, adverse reactions to foods, insect hypersensitivity, drug or vaccine reactions, or contact dermatitis. Nonimmunologic factors include cold, heat, pressure (dermatographism), exercise, or stress. Idiopathic factors are common.



Diagnosis image



Differential Diagnosis


Erythema multiforme, vasculitis, lymphoma, sterile or infectious granulomas, amyloidosis

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Urticaria

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