• A cutaneous lesion or lesions involving edema of the epidermis and/or dermis presenting with rapid onset and pruritus, returning to normal skin appearance within 24 hours
  • Pathophysiology is primarily mast cell degranulation and subsequent histamine release.
  • Angioedema may occur with urticaria, which is characterized by sudden pronounced erythematous nonpitting edema of the lower dermis and subcutis; may take up to 72 hours to remit
  • Pruritus and burning are more commonly associated with urticaria; pain more often with angioedema
  • Lesions can occur on any part of the body.
  • Urticaria can be classified as acute or chronic.
    • Acute: if lesions recur within <6 weeks
    • Chronic: recurring lesions that persist for >6 weeks
  • Three main causal categories of urticarial lesions
    • Immunoglobulin E (IgE) mediated
    • Non-IgE immunologically mediated
    • Nonimmunologically mediated
  • Underlying etiology may be difficult to pinpoint, although in some cases possible.
  • For those with chronic urticaria, 40% have concurrent angioedema
  • Etiology of urticaria is either spontaneous or induced.
  • System(s) affected: integumentary
  • Synonym(s): hives; wheals



  • Equally distributed across all ages: female > male (2:1 in chronic urticaria)
  • In 20% of patients, chronic urticaria lasts >10 years.


  • 5–25% of the population
  • Of people with urticaria, 40% have no angioedema, 40% have urticaria and angioedema, and 20% have angioedema with no urticaria.
  • Up to 3% of the population has chronic idiopathic urticaria.

Etiology and Pathophysiology

  • Mast cell degranulation with release of inflammatory reactants, which leads to vascular leakage, inflammatory cell extravasation, and dermal (angioedema) and/or epidermal (wheals/hives) edema
  • Histamine, cytokines, leukotrienes, and proteases are main active substances released.
  • If release of histamine and other mediators occurs in the dermis, urticaria lesions result. If release occurs deep in the dermis, then angioedema develops.
  • Acute spontaneous urticaria (ASU)
    • Bacterial infections: strep throat, sinusitis, otitis, urinary tract
    • Viral infections: rhinovirus, rotavirus, hepatitis B, mononucleosis, herpes
    • Foods: peanuts, tree nuts, seafood, milk, soy, fish, wheat, and eggs; tend to be IgE-mediated; pseudoallergenic foods such as strawberries, tomatoes, preservatives, and coloring agents contain histamine.
    • Drugs: IgE-mediated (e.g., penicillin and other antibiotics), direct mast cell stimulation (e.g., aspirin, NSAIDs, opiates)
    • Inhalant, contact, ingestion, or occupational exposure (e.g., latex, cosmetics)
    • Parasitic infection; insect bite/sting
    • Transfusion reaction
  • Chronic spontaneous urticaria (CSU)
    • Chronic subclinical allergic rhinitis, eczema, and other atopic disorders
    • Chronic indolent infections: Helicobacter pylori, fungal, parasitic (Anisakis simplex, strongyloidiasis), and chronic viral infections (hepatitis)
    • Collagen vascular disease (cutaneous vasculitis, serum sickness, lupus)
    • Thyroid autoimmunity, especially Hashimoto
    • Hormonal: pregnancy and progesterone
    • Autoimmune antibodies to the IgE receptor α chain on mast cells and to the IgE antibody
    • Chronic medications (e.g., NSAIDs, hormones, ACE inhibitors). NSAID sensitivity demonstrated almost in half of adults with chronic urticaria and presents with a worsening of symptoms 4 hours after ingestion.
    • Malignancy
    • Physical stimuli (cold, heat, vibration, pressure) in physical urticaria
  • Chronic inducible urticaria (CIU)
    • Dermatographism: “skin writing” or the appearance of linear wheals at the site of any type of irritation. This is the most common physical induced urticaria.
    • Cold urticaria: Wheals occur within minutes of rewarming after cold exposure; 95% idiopathic but can be due to infections (mononucleosis, HIV), neoplasia, or autoimmune diseases.
    • Delayed pressure urticaria: Urticaria occurs 0.5 to 12 hours after pressure to skin (e.g., from elastic or shoes), may be pruritic and/or painful, and may not subside for several days.
    • Solar urticaria: from sunlight exposure, usually UV; onset in minutes; subsides within 2 hours
    • Heat urticaria: from direct contact with warm objects or air; rare
    • Vibratory urticaria/angioedema: very rare; secondary to vibrations (e.g., motorcycle)
    • Cholinergic urticaria: due to brief increase of core body temperature from exercise, baths, or emotional stress. This is the second most common induced urticaria.
    • Adrenergic urticaria: caused by stress; extremely rare; vasoconstricted, blanched skin around pink wheals as opposed to cholinergic’s erythematous surrounding
    • Contact urticaria: wheals at sites where chemical substances contact the skin, may be either IgE-dependent (e.g., latex) or IgE-independent (e.g., stinging nettle)
    • Aquagenic and solar urticaria: small wheals after contact with water of any temperature or UV light, respectively; rare

No consistent pattern known: Chronic urticaria has increased frequency of HLA-DR4 and HLA-D8Q MHC II alleles.

General Prevention

Avoidance of known triggers is the mainstay of prevention.

Commonly Associated Conditions

  • Angioedema (common)
  • Anaphylaxis (somewhat common)

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