Please confirm topic selection

Are you sure you want to trigger topic in your Anconeus AI algorithm?

Please confirm action

You are done for today with this topic.

Would you like to start learning session with this topic items scheduled for future?

Updated: Dec 16 2021

Urticaria

Images
https://upload.medbullets.com/topic/120069/images/hives.jpg
https://upload.medbullets.com/topic/120069/images/hives2010.jpg
  • Snapshot
    • A45-year-old woman with a history of systemic lupus erythematous presents to her dermatologist’s office with hives. She complains that this is the “worst it’s ever been.” She has been having episodes of itchy rashes on and off for about 6 months now. On physical exam, her entire back is covered with raised, red wheals. Some are annular. The lesions are blanching and intensely pruritic. She denies any difficulty breathing or any GI symptoms. She has a history of childhood asthma and hypothyroidism, currently on levothyroxine. The lesions usually resolve spontaneously, but this episode is particularly pruritic. She is given an anti-histamine.
  • Introduction
    • Pruritic inflammation of the skin commonly known as “hives
    • Characterized by superficial, localized edema and erythema
    • Timeline
      • acute is < 6 weeks
      • chronic is > 6 weeks
    • Triggers of acute urticaria
      • drugs
      • food
      • viral infection
      • recent illness
      • insect bite
      • emotional stress
      • cold or heat
      • alcohol ingestion
      • pregnancy
      • exposure to other allergens (pet dander, dust, mold, or chemicals)
      • sun
    • Chronic urticarial is usually idiopathic
      • more likely to be associated with autoimmunity
  • Epidemiology
    • Most frequent dermatologic disorder seen in the emergency room
  • Etiology
    • Pathogenesis
      • involving dermis and epidermis
      • mast cell and basophil release of vasoactive substances
        • histamine, bradykinin, and prostaglandins
        • intense pruritus is from histamine in the dermis
      • type I hypersensitivity reaction
    • Identified in 40-60% of acute cases and 10-20% in chronic cases
    • Many different types of urticarial with wide range of severity
      • IgE-mediated
      • chemical-induced
      • cold-induced
      • autoimmune
  • Presentation
    • Symptoms
      • history of previous urticaria
      • pruritus
      • lasts a few hours
      • resolves spontaneously
    • Physical exam
      • well-circumscribed erythema and edema on skin
      • blanching, raised, and palpable wheals
        • linear
        • annular
        • serpiginous
        • can coalesce
      • can occur anywhere on the body
      • dermotographism (urticaria from light scratching)
        • indicates very sensitive skin
      • assess for angioedema of lips
      • assess for mucosal lesions
      • may have neutrophilic vasculitis
        • painful as well as pruritic
        • purpuric and hyperpigmented lesions
        • systemic systoms such as arthralgias and GI symptoms
  • Evaluation
    • Labs or biopsy not indicated for acute urticaria unless diagnosis is unclear
    • ↑ IgE
    • For chronic or recurrent urticarial
      • test ESR, TSH, and ANA
    • Biopsy of lesion
      • dermal edema
      • lymphatic channel dilation
  • Differential Diagnosis
    • Hereditary angioedema
    • Contact dermatitis
    • Multiple insect bites
    • Erythema multiforme
  • Treatment
    • If known, discontinue offending agent
    • If concern for airway compromise
      • epinephrine
    • Anti-histamines
      • second generation > first generation
        • second generation anti-histamines are less sedating and have negligible anticholinergic effects when compared to first generation anti-histamines
    • For urticarial vasculitis
      • NSAIDs
      • methotrexate
      • colchicine
      • dapsone
  • Prevention, and Complications
    • Prevention
      • avoid known triggers
      • take second generation anti-histamine daily
    • Complications
      • life-threatening angioedema
      • neutrophilic vasculitis
        • associated with arthritis, renal disease, and hypercomplementemia
        • often lasts > 24 hours
  • Prognosis
    • Most resolve spontaneously
Card
1 of 0
Question
1 of 3
Private Note