allergic rhinitis Flashcards
non allergic rhinitis
1) drug induced
- aspirin/NSAIDs, antihypertensives, oral contraception, prolong use of topical decongestants, antidepressants, sedatives, phosphodiesterase 5 inhibitors (for ED)
2) recreational drug: cocaine
3) change in hormone level: pregnancy, menstrual cycle
4) structural: septum deviation, polpys
5) Trauma
6) idiopathic/vasomotor
- sudden onset/offset of watery discharge
viral rhinitis
- infectious agent
- infection -> inflammation of nose & throat lining -> trigger mucous prodcuction
pathophysiology of AR - sensitisation phase
. 1st exposure, no clinical symptoms
. actions of allergen
1) activate naive CD4 T cells -> differentiate into antigen specific TH2 cells
2) activate B cells -> produce allergen specific IgE -> enter circulation -> bind to mast cell & basophil through high affinity IgE receptors -> formation of memory TH2 & IgE B cells
pathophysiology of AR - re-exposure phase
- allergen bind to IgE receptors on mast cells in nasal passage -> IgE & high affinity IgE receptor cross-linking -> mast cell activation & degranulation
- actions of activated mast cell
1) degranulation
. release pre-stocked mediators (protease, histamines)
. histamines interact with nasal sensory neurons & vasculature
. first clinical signs: itch, paroxysmal sneezing, vasodilation, plasma exudate
2) formation of more mediators
. PGD (esp PGD2): rhinorrhea, congestion
. kinin (bradykinin): itchy/sore throat, congestion
. neuropeptides: vasodilation -> congestion - recruit inflammatory granulocytes
. eosinophils, neutrophils
. infiltrate site of inflammation, produce more mediators (cytokines)
. late phase allergic reaction - persistent inflammation due to continuous exposure
. lower threshold for allergen trigger
signs and symptoms of AR
. due to vasodilation, mucous production, mucous oedema, stimulation of itch centre
1) rhinorrhea: watery, clear
2) congestion
- bilateral, can move from one nose to another
- severe: total blockage -> breathe from mouth -> dry mouth -> nasal speech & bad breath
- rare: anosmia (loss of smell)
3) pruritus of eyes, nose, ears
4) ophthalmic: itch, irritation, allergic conjunctivitis (bilateral, red, watery)
5) headache
6) pain
7) post nasal drip
8) cough
9) epistaxis: nose bleed
- mucous inflammation & hyperkamia (> blood vessels)
10) allergic shiners
- orbital oedema
- darkening under eyelids: subcutaneous venous dilation cuz of venous congestion
- blueish swelling/darkening: impaired nasal venous outflow
11) Dennis-morgan folds
- lines below eyeline
12) allergic salute
- repeated rub/push up tip of nose due to nasal itch
13) allergic crease
- permanent crease due to allergic salute
- continuous upwards & outwards movement of lips & teeth -> overbite
14) reversible spontaneously/with treatment
15) worsen in morning -> better in day -> worsen at night
signs and symptoms of AR
. due to vasodilation, mucous production, mucous oedema, stimulation of itch centre
1) rhinorrhea: watery, clear
2) congestion
- bilateral, can move from one nose to another
- severe: total blockage -> breathe from mouth -> dry mouth -> nasal speech & bad breath
- rare: anosmia (loss of smell)
3) pruritus of eyes, nose, ears
4) ophthalmic: itch, irritation, allergic conjunctivitis (bilateral, red, watery)
5) headache
6) pain
7) post nasal drip
8) cough
9) epistaxis: nose bleed
- mucous inflammation & hyperkamia (> blood vessels)
10) allergic shiners
- orbital oedema
- darkening under eyelids: subcutaneous venous dilation cuz of venous congestion
- blueish swelling/darkening: impaired nasal venous outflow
11) Dennis-morgan folds
- lines below eyeline
12) allergic salute
- repeated rub/push up tip of nose due to nasal itch
13) allergic crease
- permanent crease due to allergic salute
- continuous upwards & outwards movement of lips & teeth -> overbite
14) reversible spontaneously/with treatment
15) worsen in morning -> better in day -> worsen at night
risk factors for AR
1) genetic & family history
. atopy: family history of allergy, prone to sensitisation by environmental factors
- 1 parent about 35% chance, both parents > 50%
. filaggrin gene mutation
- filaggrin: skin barrier protein
- more susceptible to AD and AR
- mutation: skin less able to retain water, skin dry & oedema, cannot shield well against pathogens
2) environmental
- pollution, irritants
- more prevalent in developing countries
3) exposure to allergen
complications for AR
1) asthma
- AR sign of poorly controlled asthma or developing factor for asthma
2) AD
3) atopic march
- Ig response
- AD & food allergy when young likely to develop asthma and AR when older
4) sinusitis
- decreased nasal secretion clearance -> bacterial infection
5) acute otitis media
6) eustachian tube infection & oedema
7) sleep apnea
- block nose -> disturb sleep -> snoring, dry mouth, morning fatigue
8) allergic creases
diagnosis for AR
1) history
2) examination
3) allergy testing
- for patients not responding to treatment/diagnostic uncertainty
- skin prick: stop antihistamine 4 days before, little swelling/red bumps on skin within 15 mins and resolve in 2-3 hrs, okay for children but not for pregnant women
- cannot stop antihistamine: radioallergoabsorbent (RAST) test for specific IgE
ARIA classification for AR
- 2/> of symptoms > 1 hr on most days
1) watery rhinorrhea
2) paroxysmal sneezing
3) nasal obstruction
4) nasal pruritus
5) +/- conjunctivitis
classification of AR (intermittent, persistent, mild, moderate-severe)
. mild: don’t affect QoL
. moderate - severe: affect QoL
. intermittent: < 4 days/wk or < 4 wks
. persistent: < 4 days/wk and > 4 wks
differential diagnosis for AR
. viral URTI
. non allergic rhinitis
. nasal polyps
- obstruction doesn’t clear
. deviated septum
- no rhinorrhoea, itching, sneezing
. presence of foreign body
- child, unilateral discharge
when to refer for AR
1) special population
- child < 12 yo
- pregnant women (change hormone)
2) non allergic rhinitis symptoms
- mucopurulent discharge, unbearable facial pain, anosmia, epistaxis, high fever
3) treatment induced rhinitis
4) underlying LRTI
5) not responding to treatment/worsening symptoms
6) side effects of treatment
non pharmcotherapy for AR
1) dust mites
- prevent dust accumulation
- protect patient: impermeable covers
- wash beddings in hot cycle (> 55 degrees) to kill dust mites
- vacuum with HEPA filter
- dust mite poison
- control humidity 35-50%
2) cockroach
- parts of cockroach, saliva, faeces, urine
- cockroach trap
- careful food preparation
- pest control
3) pets
- dander (flakes of skin), urine, faeces, saliva, not fur
- separation
- bathe pet regularly
- wash hands after touching pet
4) mould
- no potted plants
- remove visible mould (NaOH)
- dark damp places
- dry carpets
- ventilation
- control humidification
pharmacotherapy for AR - oral H1 antihistamines
. not for congestion
. 2nd gen preferred
- less sedating & anticholinergic effect
- longer t1/2 = less frequent dosing
