Urticaria/Angioedema Flashcards
What is urticaria?
Also known as hives or wheals, which is in basic terms oedema in the dermis
How quickly does urticaria develop?
Over a few minutes
What is the difference between urticaria and angioedema?
Urticaria is intensely itchy, whereas angioedema is rarely itchy
What are features of an urticarial rash?
Develop acutely over a few minutes
- Cutaneous swellings/weals
- Intense pruritis
- No surface change or scaling
-
Erythematous
- If very acutely swollen, may appear flesh-coloured or whitish and people often mistake them for blisters.
What are features of angioedema?
Soft tissue swelling (oedema) especially around the eyes, the lips and the hands but this is rarely itchy
What is the pathogenesis of urticaria?
Degranulation of cutaneous mast cells which releases a number of inflammatory mediators (including histamine) which in turn make the dermal and sub-dermal capillaries leaky. In most cases the underlying cause is autoimmune (patients develop autoantibodies against the high-affinity IgE receptor α-subunit of the mast cell).
What are phsyical causes of urticaria?
- Cold
- Deep pressure
- Stress
- Heat
- Sunlight
- Chemical irritants
How would you manage someone with acute urticaria (<6 weeks)?
- Treat underlying cause - remove cause
- Avoid salicylates/opiates/NSAIDs - make it worse
- Oral antihistamines - certrizine
How would you manage angioedema?
If not hereditary:
- IM adrenaline
- IV steroids
What is hereditary angioedema?
A rare autosomal dominant condition due to an inherited deficiency of C1 esterase inhibitor (C1-INH) which causes massive activation of the complement system, increased bradykinin levels and thus angio-oedema
What are features of hereditary angioedema?
- Attacks of non-itchy cutaneous angioedema - lasts for 72 hours
- Recurrent abdo pain
- NO URTICARIA
How would you manage someone with an acute attack of hereditary angioedema?
- C1 esterase inhibitor
- FFP
- Noveal agents - Icatibant, Ecallantaide
What maintenance treatment would you use for hereditary angioedema?
Anabolic steroids - increase hepatic synthesis of C1 esterase inhibitor
How would you manage someone with chronic urticaria?
