Urticaria and angioedema Flashcards
difference between urticaria and angioedema
v similar and can overlap
urticaria is more common and is less severe. only affects epidermis and dermis whereas angioedema affects subcut tissue. urticaria is always itchy. angioedema is sometimes itchy but usually painful
which one can affect mucosa (particularly eyelids and lips)
angioedema
how does angioedema vs urticaria look
angioedema: red swellings below surface of skin
urt: red blotchy patches on skin
urticaria aka
hives
urticaria time scale
acute - resolves within 48 h
chronic: >6wk
what cells involved
mast cells -> release histamine
also basophils
triggers acute urticaria
- allergies (food, bite, sting, meds)
- viral infection
- skin contact with chemicals, nettles, latex
- physical stimuli: pressure, cold, heat, dermatographism
triggers chronic urticaria
- medication (allopurinol, fluoxetine, penicillin)
- stress
- infection
- autoimmune
- dermatographism
- vibration
- sun exposure
- hot/cold water
physical examination you can do
elicit dermatographism
(scratch the skin)
(localized hive-like reaction when scratching skin)
rx urticaria
treat cause
remove aggravating factors
non-sedating antihistamines
meds that cause acute urticaria
NSAIDs, ACEi
examples of non sedating histamines
cetirizine
loratadine
fexofenadine
urticaria can often be a feature of…
anaphylaxis
anaphylaxis rx
adrenaline 0.5ml 1:1000 (500ug) IM. repeat 5 mins later if necessary
chlorphenamine 10-20mg IV as an adjunct
allergic causes of angioedema
- allergic (food, meds NSAIDs, insect bites, latex)
- non-allergic ACEi*
- idiopathic
*omg FINALLY know why CCBs used for afrocaribbean. angioedema more common as AE in this group of people
