Angioedema

On this page

Angioedema - Swelling Showdown

  • Localized, transient, non-pitting subcutaneous or submucosal swelling.
  • Key features: Asymmetric, well-demarcated.
  • Classification:
    • Histaminergic (Allergic):
      • Most common.
      • Pruritus, urticaria often present.
      • Responds to antihistamines, steroids, epinephrine.
    • Non-histaminergic (Bradykinin-mediated):
      • No pruritus/urticaria.
      • Poor response to antihistamines/steroids.
      • Types:
        • Hereditary Angioedema (HAE): C1-INH deficiency/dysfunction.
        • Acquired Angioedema (AAE): C1-INH deficiency.
        • ACE inhibitor-induced: Commonest bradykinin type. Angioedema of the lower lip

⭐ ACE inhibitor-induced angioedema can occur at any time, even years after initiating therapy.

Angioedema - Cascade Chaos

  • Two main cascades: Mast cell (histaminergic) vs. Bradykinin-mediated.
  • Mast Cell Pathway:
    • Mediators: Histamine, Prostaglandins (PGs), Leukotrienes (LTs).
    • Clinical: Urticaria & pruritus common. Responds to antihistamines, steroids, epinephrine.
  • Bradykinin Pathway:
    • Mediator: Bradykinin (via contact system activation or ↓degradation).
    • Clinical: No urticaria/pruritus. Poor response to standard allergy Rx.
    • Key Causes: ACE inhibitors, Hereditary Angioedema (HAE: C1-INH deficiency/dysfunction), Acquired Angioedema (AAE).

⭐ In HAE (Types I & II), C4 levels are characteristically low during acute attacks and for screening.

Angioedema - The Usual Suspects

TypeCause (Mediator)C1-INH LvlC1-INH FxnC4UrticariaNotes/Rx
HAE Type IAD C1-INH def (Bradykinin)NoC1-INH conc, Icatibant
HAE Type IIAD C1-INH dysfxn (Bradykinin)N/↑NoC1-INH conc, Icatibant
HAE (nC1-INH)F12 mut; Estrogen (Bradykinin)NNNNoTranexamic acid, Icatibant
AAE Type IC1-INH use (Lymphoprolif. C1q↓)NoRx underlying; C1-INH conc
AAE Type IIAnti-C1-INH Ab (C1q↓)N/↓NoImmunosuppression
AllergicHistamineNNNYesAntihistamines, Steroids, Epi
ACE-I InducedBradykinin accum.NNNNoStop ACE-I; Icatibant. 📌 Angioedema Caused by Enzyme inhibition
IdiopathicHistaminergic/Non-hist.NNNVariableTrial antihistamines; if fails, bradykinin path.

Angioedema - Spotting Swells

  • Localized, transient, non-pitting edema of deep dermis, subcutaneous/submucosal tissues.
  • Sites: Face (lips, eyelids, tongue), larynx, extremities, GIT. Resolves 24-72 hrs.
  • Triggers: Allergens, drugs (ACEi, NSAIDs), C1-INH deficiency (HAE).
  • Key Distinction:
    • With Urticaria: Mast cell-mediated (histamine). Often allergic/idiopathic.
    • Without Urticaria: Bradykinin-mediated (e.g., HAE, ACEi-induced).
      • Abdominal pain, N/V/D common in HAE (bowel wall edema).
      • Laryngeal edema: Stridor, dysphonia. Airway emergency!

⭐ Bradykinin, not histamine, mediates HAE & ACEi-AE; antihistamines/steroids ineffective.

  • Diagnosis: Clinical. History (triggers, family Hx, drug Hx), exam.
    • HAE workup (if recurrent, no urticaria, +ve family Hx): ↓C4 (screening), then C1-INH level & function.

Angioedema - Swelling Solutions

  • Types & Key Rx:
    • Allergic (histaminergic): Antihistamines, Steroids, Epinephrine (0.3-0.5 mg IM).
    • Bradykinin-mediated (HAE, ACEi):
      • HAE Acute: C1-INH concentrate (20 IU/kg IV), Icatibant (30 mg SC), Ecallantide (30 mg SC), FFP.
      • ACEi: Stop ACEi.
  • Acute Attack Management:
  • HAE Long-Term Prophylaxis:
    TherapyExamplesKey Point
    Attenuated AndrogensDanazol↑ C1-INH synthesis
    AntifibrinolyticsTranexamic AcidInhibit plasmin
    C1-INH ConcentrateBerinert, CinryzeReplacement therapy (IV/SC)
    Kallikrein InhibitorLanadelumabMAb, SC inj.

⭐ Hereditary Angioedema (HAE) is bradykinin-mediated, thus unresponsive to antihistamines, corticosteroids, and epinephrine.

High‑Yield Points - ⚡ Biggest Takeaways

  • Angioedema: Acute, localized swelling of dermis, subcutaneous tissue, or submucosa.
  • Bradykinin-mediated (e.g., HAE, ACE-inhibitor induced): Non-pruritic, no urticaria; unresponsive to antihistamines/steroids.
  • Mast cell-mediated (allergic): Often with urticaria, pruritus; responds to antihistamines, steroids, epinephrine.
  • Hereditary Angioedema (HAE): C1-inhibitor deficiency/dysfunction causes ↑ bradykinin.
  • Airway compromise: A life-threatening emergency requiring prompt intervention.
  • Acute HAE Tx: C1-INH concentrate, icatibant, ecallantide; FFP if others unavailable.

Practice Questions: Angioedema

Test your understanding with these related questions

Not typically associated with Ludwig's angina is

1 of 5

Flashcards: Angioedema

1/2

Allergic rhinitis can lead to _____ otitis media

TAP TO REVEAL ANSWER

Allergic rhinitis can lead to _____ otitis media

serous

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial