Hereditary Angioedema
Overview
Recurrent episodes of angioedema
Without urticaria
Most often affects the skin, respiratory tract and GIT
Swelling is self-limiting
Resolves 2 to 5 days without treatment
Pathogenesis
Deficiency/dysfunction of C1 inhibitor
This leads to excess bradykinin (vasodilator)
When to suspect
Recurrent angioedema without urticaria
Unexplained colicky abdominal pain lasting 1 to 3 days
Unexplained airways oedema
Recurrent angioedema in young patient < 30 years
Diagnosis
Suggestive history
Suggest physical findings during episode
Bloods showing low C4 plus decreased C1-NH protein or function
Antihistamines and glucocorticoids don’t help
Bloods
Two sets at least a month apart of
C4 (the natural substrate for C1 esterase)
C1-INH protein (or "antigenic") levels, and
C1-INH function
If suspicion is low
C4 is enough
Normal C4 during an episode excludes HAE
If suspicion is high
recurrent episodes of angioedema
Episodes do not correlate with NSAIDs
History does not suggest food, latex or other allergic cause
Positive family history of HAE
ACEI
Increases susceptibility to developing angioedema
DDx
Allergic reactions
Wheeze, urticaria, vomiting, diarrhoea, hypotension
Rapid onset
Precipitating event (meal, insect, new medication)
Anaphylaxis
Idiopathic angioedema
Complement normal
Drug-induced angioedema
ACEI
NSAIDs
Allergic contact dermatitis
Autoimmune conditions
FAcial, periorbital and sometimes hand oedema
SLE, Dermatomyositis, Sjogren’s
Thyroid
Superior vena cava
Cheilitis granulomatosa
Trichinosis
Acute Treatment
C1-INH concentrate
Recombinant human C1-INH
Icatibant (Bradykinin antagonist)
Ecallantide (Kallikrein inhibitor)
