atopy and allergy Flashcards
Atopy is a genetic tendency to make – reactions by which it clinically manifest as — , — , —
- laboratory is high total –
- measurement of total Ige rarely useful , — rather than lab test will help determine the symptoms of the allergic
IgE
rhinitis, asthma or
eczema ( most common allergic reaction then we will have the hay fever n then asthma )
IgE
history
urticaria and angioedemia -frquently not allergy :
Usually due to – release from – cells
➢ Urticaria – – release
➢ Angioedema – histamine release in. –
- Histamine causes — and increased —
histamine release from mast cells
superficial
subcutis
vasodilation and increased vascular permeability and itch
so why’s there such confusion:
- Doctors and patients equate urticaria and angioedema with allergy
- Many doctors don’t understand the
difference between allergy and sensitisation - Doctors and patients confuse allergy and side effects or intolerance
— is a common sign in inducible urticaria
dermographism
urticaria +/- agioadema:
➢ Seen in – of allergic reactions
➢ However most urticaria —
➢ 25% of population will have urticaria at least
➢ 1% at least will have chronic urticaria
➢ Children – most commonly –
➢ Adults – most common cause – (Spontaneous or Inducible)
➢ Causes huge anxiety
80%
non allergic
viral infection
chronic urticaria
its all in the history:
Allergy can cause acute (within – )
➢ urticaria & angioedema,
➢ often with other symptoms of allergy
Chronic urticaria +/- angioedema NOT caused by — – often waken with it in the morning
➢ Chronic spontaneous urticaria
➢ Chronic inducible urticaria
➢ Other
- allergy focused history includes :
➢ What happened? Exactly
➢ Can symptoms be explained by IgE/ histamine?
➢ When did it happen?
➢ Relationship to possible allergens
➢ Co-factors eg exercise; NSAIDs; Alcohol
➢ What treatment was needed
➢ Subsequent exposure & effect
within 1 hour
no caused by allergy
EATERS:
E –
A —
T —
E —
R —
S —
red flags include:
exposure
allergen ( what is likely )
Timing
environment
reproducibility
symptoms
red flags: anaphylaxis , airways , breathing , circulation
— : history of allergic reactions to the substance.
➢ History substantiated by demonstration of allergen specific IgE (SPT or blood)
➢ May need challenge to confirm or exclude
—: allergen specific IgE present in
the absence of clinical symptoms.
➢ Tolerance maintained by regular exposure
allergy
sensation
sensitisation:
➢ Weakly positive – tests/specific –
tests often NOT clinically relevant
➢ People with eczema have grossly elevated total – – causes — specific IgE
➢ Cutting out food to which person is sensitised can cause allergy due to –
➢ Causes huge anxiety
skin and IgE blood test
IgE
false +ve
lose tolerance
diagnosis of allergy includes
1- –
2- —
3- — and —
4- – challenge
5- double blind — controlled challenge
how to NOT diagnose allergy:
- — testing
- — testing
- —
- —
- – testing of specific IgE is not advised
history
skin prick test
allergen specific IgE
food/exposure & system diary
food challenge
placebo
IgE
Vega
kinesiology ( body movement )
hair analysis
broad
allergy vs side effects:
➢ Particularly important with drug allergy
➢ Leads to inappropriate label of allergy
➢ Using – because of spurious
allergy
➢ Contributing to emergence of –
➢ Impaired outcomes when labelled allergic to penicllins – often get second best treatment.
➢ Eg. — with co-amoxiclav.
reserve antibiotics
resistance
diarrhoea
1-management of anaphylaxis:
➢ A, B, C (D, E) & call for help
➢ Lie patient flat, unless too breathless
➢ High flow –
➢ – IM – repeat if required
➢ Fluid bolus
➢ — – for skin rash – after resus
➢ — – to prevent late reaction
Prompt adrenaline saves lives
2- why do ppl die of allergies:
➢ Incomplete — on allergen
avoidance
➢ Poorly controlled –
➢ No — available / not given
( ABDCE refers to airway breathing disability circulation exposure )
oxygen
anderaline
antihistamins
cotocosteriods
info
asthma
adrenaline
severity of allergic reactions:
➢ Reactions do not inevitably get worse
➢ Reaction severity affected by:
➢ — of allergen
➢ Asthma/chest –
➢ Exacerbating factors- — , — , —
➢ – inhibitors; as —
➢ Prompt treatment/emergency plan
dose
status
excersise NSAIDS alchohol
ACE inhibitors as beta blockers
allergy mimics - urticaria & angioedma:
1-Chronic Urticaria/Angioedema
-Chronic Spontaneous Urticaria & Angioedema
-Chronic Inducible Urticaria & Angioedema
-Urticarial Vasculitis ( – urticaria)
- ( — diseases)
2-Angioedema only
— Deficiency
Medications – ACEi (BP / renal & heart protection)
atypical
autoinflamamotry
C1 inhibitor deficiency
urticaria - typical :
➢ Each lesion –
➢ No – on resolution
➢ No – upset
Associated with
➢ Allergy if –
➢ – (non-allergic) urticaria
urticaria - atypical:
➢ Lesions –
➢ – on resolution
➢ — response
➢ Need to exclude –
➢ – upset (temps etc)
➢ – response
➢ –
➢ — disease
<24
no bruising
systemic
acute
chronic
>24
bruising
acute phase response
vasculitis
systemic
acute phase response
episodic
autoinflammatory
