Cite this page
FeedbackHereditary angioedema (HAE) is an episodic swelling disease associated with the deficiency or malfunction of complement 1 esterase inhibitor (C1-INH). In contrast to acquired angioedema, which is a secondary process, HAE is associated with genetic variations. Initial laboratory assessment involves testing for C1-INH levels, complement 4 (C4) levels, functional C1-INH activity, and possibly C1q levels.
Quick Answers for Clinicians
Which testing algorithms are related to this topic?
Diagnosis
Indications for Testing
- Recurrent angioedema in the absence of urticaria of
- Subcutaneous tissues
- Systemic organs
- Mouth, larynx, or pharynx
- Family history of angioedema
- Unexplained episode of laryngeal edema
Laboratory Testing
- Initial testing
- Complement 1 esterase inhibitor (C1-INH), complement 4 (C4)
- Decreased levels suggest hereditary angioedema
- Confirm with repeat testing of C1-INH and C4
- If family history present, consider functional testing for typing
- Functional C1-inhibitor activity
- Assists with determination of hereditary angioedema type
- Consider C1q testing when family history is absent
- Later age of onset and low C1q suggest acquired angioedema
- Early age of onset and normal C1q suggest familial angioedema
- If all results are normal
- Repeat C4, C1-INH testing during attack
- Consider other types of angioedema (eg, autoimmune disorder)
- Complement 1 esterase inhibitor (C1-INH), complement 4 (C4)
- Genetic testing – not necessary for diagnosis
Differential Diagnosis
- Cutaneous edema
- Allergic urticaria/angioedema
- Drug-induced angioedema (eg, angiotensin-converting enzyme [ACE] inhibitors, nonsteroidal anti-inflammatory drugs [NSAIDs])
- Contact dermatitis
- Acquired angioedema
- Lymphoproliferative disorders (lymphoma, B-cell and T-cell lymphomas)
- Autoimmune disease
- Neoplasia
- Urticarial vasculitis associated with angioedema
- Idiopathic or cold-induced angioedema
- Cellulitis
- Parasitic infection (eg, Trichinella spp)
- Autoimmune conditions
- Laryngeal edema – peritonsillar abscess
Background
Epidemiology
- Incidence – 1/50,000
- Age
- Congenital form – usually occurs in childhood
- Acquired form – onset occurs later
- Sex – M:F, equal
Risk Factors
- Genetics
- Pressure applied to an extremity
- Stress
- Ingested estrogens, pregnancy
- Lymphoproliferative disorder
Inheritance
- Autosomal dominant inheritance
- 25% are de novo variants
- Variants in SERPING1 gene
Classification
- Hereditary angioedema (HAE) types
- Type 1 – low complement 1 esterase inhibitor (C1-INH) level and low function (85%)
- If C1q is also low, suspect acquired angioedema
- Type 2 – normal C1-INH level but low function (15%)
- Type 3 (familial angioedema) – normal C1-INH and normal function (rare)
- Type 1 – low complement 1 esterase inhibitor (C1-INH) level and low function (85%)
Pathophysiology
- C1-INH
- Multispecific, protease inhibitor
- Regulates the enzymes of the complement, coagulation, fibrinolytic, and kinin-forming systems, including
- C1r and C1s subunits of activated first component of complement
- Activated Hageman factor (factor XIIa) and Hageman factor fragments
- Activated plasma thromboplastin antecedent (PTA or factor XIa)
- Prekallikrein (Fletcher factor)
- Plasmin
- Possible disorders associated with C1-INH include
- HAE
- Hereditary quantitative deficiency or qualitative defect in C1-INH
- Deficiency of functionally active component may lead to life-threatening angioedema
- Acquired C1-INH deficiency
- Qualitative defect in C1-INH
- Associated with a variety of diseases, including lymphoid malignancies
- HAE
Clinical Presentation
- Symptoms typically begin in childhood, worsen in puberty, and have an unpredictable course throughout adulthood
- Transient, recurrent attacks of nonpruritic, deep-seated swelling of various tissues occur throughout the body without the presence of urticaria
- Typically involves arms, legs, hands, trunk, face, mouth, larynx, airway, genitals, and tongue
- Gastrointestinal tract often involved, with recurrent episodes of cramping, abdominal pain, nausea, and emesis (most frequent presenting complaint in children)
- Most frequent cause of death is airway obstruction secondary to laryngeal edema
- Presence of autoimmune diseases (especially glomerulonephritis) is higher in these patients
- Typical and predictable course
- Many attacks, preceded by prodrome (tingling sensation)
- Swelling gradually increases over the first 24 hours, then gradually subsides over the next 48-72 hours
ARUP Laboratory Tests
Primary Tests
Aid in diagnosis of hereditary angioedema (HAE)
Test for C1-esterase inhibitor (C1-INH) levels and complement 4 (C4) levels
Method
Immunoturbidimetry/Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Quantitative Nephelometry
Aid in the diagnosis of C1q deficiency
Method
Radial Immunodiffusion
Related Tests
Diagnose hereditary angioedema (HAE)
Monitor response to therapy
Method
Quantitative Nephelometry
Aid in diagnosis of HAE
Monitor response to therapy
Method
Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Rule out a complement deficiency
Method
Quantitative Immunoturbidimetry
Follow-up test for complement activity screening when CH50 is low or absent and AH50 is normal and high suspicion remains for complement deficiency
Method
Quantitative Radial Immunodiffusion
Rule out complement component 3 deficiency
Method
Quantitative Immunoturbidimetry
Medical Experts
Contributor
Genzen
Associate Professor of Pathology (Clinical), University of Utah
Chief Operations Officer: Medical Director, Automated Core Laboratory, ARUP Laboratories
Contributor
Peterson
Assistant Professor of Pathology (Clinical), University of Utah
Medical Director, Immunology, ARUP Laboratories
References
Additional Resources
22221432
Banerji A. Hereditary angioedema: classification, pathogenesis, and diagnosis. Allergy Asthma Proc. 2011; 32 (6): 403-7.
PubMed
17976427
Bork K, Gül D, Hardt J , et al. Hereditary angioedema with normal C1 inhibitor: clinical symptoms and course. Am J Med. 2007; 120 (11): 987-92.
PubMed
17085286
Bork K. Hereditary angioedema with normal C1 inhibitor activity including hereditary angioedema with coagulation factor XII gene mutations. Immunol Allergy Clin North Am. 2006; 26 (4): 709-24.
PubMed
20667127
Bowen T, Cicardi M, Farkas H , et al. 2010 International consensus algorithm for the diagnosis, therapy and management of hereditary angioedema. Allergy Asthma Clin Immunol. 2010; 6 (1): 24.
PubMed
15943590
Boyle RJ, Nikpour M, Tang ML. Hereditary angio-oedema in children: a management guideline. Pediatr Allergy Immunol. 2005; 16 (4): 288-94.
PubMed
18220152
Castaldo AJ. Hereditary angioedema: a current state-of-the-art review, IX: the US Hereditary Angioedema Association: a message from the president. Ann Allergy Asthma Immunol. 2008; 100 (1 Suppl 2): S47-8.
PubMed
22456031
Cicardi M, Johnston DT. Hereditary and acquired complement component 1 esterase inhibitor deficiency: a review for the hematologist. Acta Haematol. 2012; 127 (4): 208-20.
PubMed
19162547
Cugno M, Zanichelli A, Foieni F , et al. C1-inhibitor deficiency and angioedema: molecular mechanisms and clinical progress. Trends Mol Med. 2009; 15 (2): 69-78.
PubMed
20593909
Ebo DG, Verweij MM, De Knop KJ , et al. Hereditary angioedema in childhood: an approach to management. Paediatr Drugs. 2010; 12 (4): 257-68.
PubMed
18241690
Frank MM. 8. Hereditary angioedema. J Allergy Clin Immunol. 2008; 121 (2 Suppl): S398-401; quiz S419.
PubMed
15730382
Gompels MM, Lock RJ, Abinun M , et al. C1 inhibitor deficiency: consensus document. Clin Exp Immunol. 2005; 139 (3): 379-94.
PubMed
22305226
Longhurst H, Cicardi M. Hereditary angio-oedema. Lancet. 2012; 379 (9814): 474-81.
PubMed
23636922
Tse K, Zuraw BL. Recognizing and managing hereditary angioedema. Cleve Clin J Med. 2013; 80 (5): 297-308.
PubMed
24565617
Zuraw BL, Banerji A, Bernstein JA, et al. US Hereditary Angioedema Association Medical Advisory Board 2013 recommendations for the management of hereditary angioedema due to C1 inhibitor deficiency. J Allergy Clin Immunol Pract. 2013; 1 (5): 458-67.
PubMed
23726531
Zuraw BL, Bernstein JA, Lang DM , et al. A focused parameter update: hereditary angioedema, acquired C1 inhibitor deficiency, and angiotensin-converting enzyme inhibitor-associated angioedema. J Allergy Clin Immunol. 2013; 131 (6): 1491-3.
PubMed
Panel includes C1-INH, C1-INH functional, complement component 4