Allergic diseases

1. Allergic diseases

2. • Chronic inflammatory disorder of the medium and small
airways.
• These airways are hypersensitive to certain “triggers”
in the environment.
• Usually reversible
• Asthma cannot be cured but its symptoms can be
controlled with proper environmental changes and
medication.
What is Asthma ?

3. Risk factors for Asthma
• Allergy / Atopy
• Family history of
asthma/allergy
• Perinatal exposure to tobacco
smoke
• Viral respiratory infections
• Low birth weight
• Male gender - pre-adolescence
• Low-income, urban residents
• Obesity

4. Classification of Asthma
• Intermittent -
– Asthmatics who have symptoms that occur
with a cold from time to time.
– They often grow out of the disease.
• Persistent -
– Asthmatics having symptoms at least twice a week during
the day and twice a month during the night
– These asthmatics are further classified as mild,
moderate, or severe.

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6. • Coughing
• Wheezing
• Chest tightness
• Shortness of
breath
Symptoms of Asthma

7. Asthma Triggers
• For people with asthma, exposure to
certain substances they are sensitive to
can lead to an asthma attack or
exacerbation.
• These substances are known as
triggers.
• Not all people with asthma have the
same triggers that will cause an asthma
attack.

8. Indoor air Triggers
• Environmental tobacco smoke (ETS)
• Cockroaches
• Dust mites
• Animal dander
• Mold, mildew
• Strong scented products (perfumes,
scented cleaners)

9. Outdoor air Triggers
• Ozone
• Particulate matter
• Sulfur dioxide
• Nitrogen dioxide - vehicle exhaust
• Outdoor pollens and mold

10. Additional Triggers
• Viral upper respiratory
infections
• Exercise
• Aggravating conditions -
gastric reflux, sinusitis,
rhinitis
• Diet, medication
• Cold air
• Changes in weather
• Menstrual cycle, pregnancy

11. What causes an Asthma Attack ?
• An allergic reaction to
triggers or exposures
• Airways swell and fill with
mucus and secretions
• The muscles around the
airways contract and spasm
• Airways can collapse, causing
classic symptoms, even death

12. Indications of a severe Attack
• Breathless at rest
• Hunched forward
• Talking in words
rather than
sentences
• Agitated
• Peak flow rate is
less than 50% of
normal

13. Consult with a physician to develop an
asthma management plan, which includes:
• Medication
• Education: identification of asthma
triggers & ways to reduce/avoid exposure
to your asthma triggers
• Peak flow monitoring
• Emergency plan
Managing Asthma

14. Choose not to smoke in your home or car and do not allow
others to do so either.
Avoiding secondhand Smoke

15. Peak expiratory flow (PEF) Meters
Allows theAllows the
patient topatient to
assess theassess the
status of hisstatus of his
or her asthmaor her asthma

16. Management of Asthma
 Quick-relief medications used to
treat asthma attacks and acute
symptoms
“Relievers”
 Long-term control medications
reduce the airway inflammation
that causes these symptoms
“Controllers”

17. Asthma Medications
• Quick-relief medications
– Short-acting bronchodilators
• Relax smooth muscle around the airways
• Long-term Medications
– Steroids
• Inhaled, tablets
• Anti-inflammatory
– Long acting bronchodilators
• Relax smooth muscle
– Leukotriene inhibitors
• Anti-inflammatory

18. Causes of asthma exacerbations
• Lower or upper respiratory infections
• Cessation or reduction of medication
• Concomitant medication, e.g. β-blocker
• Allergen or pollutant exposure

19. Peak flow meters
Use peak flow meters to monitor asthma and
prevent exacerbations:
• Inexpensive
• Easy to use
• Accurate
• Provide “real life” measurements at worst and
best times of the day
• Provide objective measurement of pulmonary
function
• Detect early changes of asthma worsening

20. Stages of asthma exacerbations
stage 1:
Symptoms
• Somewhat short of breath
• Can lie down and sleep through the night
• Cannot perform full physical activities without shortness
of breath
Signs
• Some wheezes on examination
• Respiratory rate, 15 (normal <12)
• Pulse 100
• Peak flows and spirometry reduced by 10%

21. Stages of asthma exacerbations
stage 2:
Symptoms
• Less able to do physical activity due to shortness of
breath
• Dyspnea on walking stairs
• May wake up at night short of breath
• Uncomfortable on lying down
• Some use of accessory muscles of respiration
Signs
• Wheezing
• Respiratory rate 18
• Pulse 111
• Peak flows and spirometry reduced by 20+%

22. Stages of asthma exacerbations
stage 3:
Symptoms
• Unable to perform physical activity without
shortness of breath
• Cannot lie down without dyspnea
• Speaks in short sentences
• Using accessory muscles
Signs
• Wheezing
• Respiratory rate 19 - 20
• Pulse 120
• Peak flows and spirometry reduced by 30+%

23. Stages of asthma exacerbations
stage 4:
Symptoms
• Sitting bent forward
• Unable to ambulate without shortness of breath
• Single word sentences
• Mentally-oriented and alert
• Use of accessory muscles
Signs
• Wheezing less pronounced than anticipated
• Respiratory rate 20 - 25
• Pulse 125+
• Peak flows and spirometry reduced by 40+%
• SaO2 91- 92%

24. Stages of asthma exacerbations
stage 5:
Symptoms
• Reduced consciousness
• Dyspnea
• Silent chest – no wheezing
Signs
• Fast, superficial respiration
• Respiratory rate >25
• Unable to perform peak flows or spirometry
• Pulse 130 - 150+
• SAO2 <90

25. Treatment of asthma exacerbations 1
Preferred treatment choices
– β2-agonists
• Inhaled by MDI or nebulizer
• Injected
– Anticholinergics
• Inhaled by MDI or nebulizer
– Corticosteroids
• Parenteral, oral or inhaled

26. Treatment of asthma
exacerbations 2
Secondary treatment choices
– Aminophylline or theophylline (oral,
parenteral)
– Leukotriene receptor antagonists (oral)
– Oxygen
– Magnesium sulfate

27. Treatment of asthma exacerbations
beta agonistsbeta agonists
Inhaled is preferred route
– MDI plus spacer, 4 - 8 puffs Q 20 min x 3
– Nebulizer, 2.5 - 5 mg albuterol Q 20 min x 3
– Epinephrine SQ, 0.3 - 0.5ml (0.01 ml/kg)
– Levalbuterol, 0.63 - 1.25 mg Q 4 - 8 hours (if
available)

28. Treatment of asthma exacerbations
anticholinergicsanticholinergics
Ipratropium
– Preferred use: combined with beta
agonist
– MDI plus spacer, 2 - 4 puffs Q 20 min x 3
– Nebulizer, 500 μg Q 20 min x 3

29. Treatment of asthma exacerbations
corticosteroidscorticosteroids
• No immediate effect
• Earliest effects 6 hours after high dose
• Oral is as effective as parenteral
• Prednisone (equivalent), 45 - 60 mg
• Higher doses have increased side effects
and no appreciable increased therapeutic
benefit
• Methylprednisolone, 1 – 2 mg/kg/24 hours

30. Treatment of asthma exacerbations
aminophylline and theophyllineaminophylline and theophylline
• Controversial:
– Added no benefit to inhaled beta agonists
– Increased complications
• Loading dose for aminophylline: 5 – 6 mg/kg over 20 -
30 min
• Maintenance dose: 0.4 mg/kg/hr (adjust for heart and
liver disease)
• Try to achieve 5 - 15 μg/ml, monitor plasma levels to
adjust dose
• Doses for theophylline similar but slightly less

31. Treatment of asthma exacerbations
leukotriene modifiersleukotriene modifiers
• Few studies
• Suggest usefulness in reducing
hospitalizations
• Montelukast, 10 mg orally
• Zafirlukast, 20 mg orally

32. Treatment of asthma exacerbations
magnesium sulfatemagnesium sulfate
• Controversial:
– Inconsistent data
• Used in very severe asthma in emergency
settings:
– FEV1 < 25% predicted
– Other signs of severe disease
• 1.2 - 2 gm IV over 10 - 20 min in 50 ml saline
• Minor side effects

33. Definition of urticaria
and epidemiology
• Urticaria affects up to 2% of the population at some time in
a lifetime
• Transitory (individual episodes < 24h duration) red skin
swellings with itching
• No desquamation, rarely affects mucous membranes
• Associated with angioedema in about 40% of cases

34. Pathophysiology of urticaria
• Most types of urticaria are due to promiscuous activation of
dermal mast cells, although basophils may also be involved
• Release of histamine and other mediators (including
eicosanoids, proteases, cytokines) causes local vasodilation,
vasopermeability, fibrin deposition, perivascular infiltration by
lymphocytes, neutrophils, and eosinophils, and pruritus
• There is minimal endothelial swelling and no leukocytoclasis

35. Substances that cause hive formation
when injected into the skin include:
• Histamine
• Leukotrienes C and D
• Platelet activating factor (PAF)
• Bradykinin
• Substance P

36. Classification of urticaria into acute
and chronic
• “Urticaria” is an umbrella term inclusive of diverse
clinical entities
• Conventionally it is broadly divided into acute and
chronic
• Chronic urticaria is conventionally defined as “daily
or almost daily urticarial eruptions occurring for 6
weeks or more”

37. Acute urticaria
• All ages; common in childhood
• Abrupt onset of urticarial eruption usually pruritic and
widespread
• Angioedema common
• Systemic symptoms (fever, malaise) also common,
depending on cause
• Duration: usually hours or days

38. Causes of acute urticaria
• Viral infections; particularly in children. In adults:
prodrome of Hepatitis B, infectious mononucleosis
(EBV)
• Drugs (NSAIDS, penicillins and derivatives,
radiocontrast media)
• Foods non–allergic (e.g., scombroid fish poisoning)
and allergic (IgE–mediated) (e.g., nuts, shellfish)
• Immunization vaccines e.g., tetanus toxoid

39. Investigation of acute urticaria
• Many cases require no investigation - the
cause is evident to patient and doctor alike
• Skin prick tests may support the diagnosis
• Serum IgE testing may also help confirm the
culprit

40. Acute urticaria: prognosis and treatment
• Many attacks of acute urticaria are solitary, and the cause is
evident and avoidable
• Facial / labial / buccal angioedema should respond to Primatene
mist spray and / or subcutaneous adrenaline administered every
10-15 min
• Severe oropharyngeal angioedema should prompt overnight
admission
• Chlorpheniramine 4 mg or diphenhydramine 50 mg by injection or
by mouth is usually sufficient to suppress even widespread
urticaria

41. Therapy of chronic
idiopathic/autoimune urticarias
• H1 receptor antagonists
• H2 receptor antagonists
• Leukotriene antagonists
• Alternate-day corticosteroids
• Cyclosporin

42. Management of chronic
urticaria
Antihistamine treatment:
• Low sedation antihistamines taken regularly - not on an
“as required” basis (desloratidine 5mg daily;
levocetirizine 5mg daily; fexofenadine 120-180mg daily)
• Sedative antihistamine such as hydroxyzine 25mg
taken before sleep if nocturnal pruritus is a problem
• In resistant cases off-label doses of low sedation antihistamines (e.g.,
360 mg fexofenadine daily) are effective and safe
• H2 antihistamines are of doubtful efficacy, but are useful in patients
with a history of corticosteroid toxicity

43. Management of chronic urticaria: what to do if
antihistamines don’t work
• Add montelukast 10mg daily: It helps some but not all
patients and adverse effects are rarely a problem
• Add doxepin 25mg at night: This tricyclic is best known as
an anti-depressant, but is a very potent H1 and H2
antihistamine, causing sedation. It should not be given with
other antidepressants
• Prednisolone: short tapering courses commencing 30mg
daily are useful to deal with the occasional temporary flare-
up

44. Management of chronic urticaria: what to
do if antihistamines don’t work, cont.
• Cyclosporin: best known for its effectiveness in
autoimmune urticaria, is also effective in non–
autoimmune chronic urticaria. Dosage 4-6mg/Kg/day,
with regular checks of renal function and blood
pressure, and a chest X-ray. It is especially valuable in
patients with chronic steroid toxicity
• Intolerance or ineffectivenes of cyclosporin:
methotrexate 10-25mg orally once weekly, or
mycophenolate mofetil 1-2g daily can be tried

45. Angioedema
• First described by Quincke in 1882
• Well-demarcated non-pitting edema
• Often caused by same pathological
factors that cause urticaria
• Reaction occurs deeper in dermis and
subcutaneous tissues
• Face, tongue, lips, eyelids most
commonly affected
• May cause life-threatening respiratory
distress

46. Causes of Angioedema
• Like urticaria – foods, drug allergy,
radiocontrast media, insect stings/bites,
infection, NSAIDs
• Associated with anaphylaxis of any cause
• Autoimmune – accompanying chronic urticaria
• Idiopathic
• ACE inhibitors – Typically without urticaria;
• C1 inhibitor deficiency – no urticaria

47. Treatment of Acute Episodes of
Angioedema
• Diphenhydramine 50 mg – repeat in 4 hours
• Prednisone 50 mg X 2 doses and stop
without any taper
• Epinephrine – if rapidly advancing
• H2 antihistamines

48. Preventive Therapy of Frequent but Mild
Episodes of Angioedema
• A non-sedating antihistamine; may double
the dose or combine them, e.g. fexofenadine
180 mg or loratadine 10 mg in a.m. and
cetirizine 10 mg mid-day and bedtime
• Add H2 - antagonist, BID
• If ineffective, diphenhydramine at 50 mg QID.
plus H2 antagonist
• If antihistamines alone are ineffective, try
adding a leukotriene antagonist (BID)

49. Prevention of Frequent and/or Severe
Episodes of Angioedema
• Diphenhydramine at 50 mg qid. If successful, taper
to lowest effective dose. Consider non-sedating
antihistamines at BID dosing
• H2 - antagonists at BID dosing may be added
• Leukotriene antagonists; if ineffective try leukotriene
synthesis inhibitors
• If refractory to above:
– Transexamic acid or epsilon amino caproic acid
(empiric therapy for non-histamine induced
idiopathic angioedema)
– Corticosteroid at 10-20 mg every other day
– Azulfidine (up to 3 grams per day) can be tried as
well

50. • Rhinitis:Rhinitis: Symptomatic disorder of the
nose characterized by itching, nasal
discharge, sneezing and nasal airway
obstruction
• Allergic rhinitis:Allergic rhinitis: Induction of rhinitis
symptoms after allergen exposure by
an IgE-mediated immune reaction;
accompanied by inflammation of the
nasal mucosa and nasal airway
hyperreactivity.

51. Allergic rhinitis: impact
• High prevalence
• Impaired quality of life
• Work and school absence
• Impaired learning
• Impaired sleeping
• Associated asthma, sinusitis, otitis

52. Allergic rhinitis co-morbidities
• Conjunctivitis
• Sinusitis
• Otitis Media
• Cough
• Asthma

53. IntermittentIntermittent
Symptoms
• < 4 days / week
• or < 4 weeks
PersistentPersistent
Symptoms
• > 4 days / week
• or > 4 weeks
MildMild
• Sleep: normal
• Daily activities (incl.
sports): normal
• Work-school activities:
normal
• Severe symptoms: no
Moderate-severeModerate-severe
• Sleep: disturbed
• Daily activities:
Restricted
• Work and school
activities: disrupted
• Severe symptoms: yes
Allergic rhinitis classification

54. Diagnosis of allergic rhinitis
• Detailed personal and family allergic
history
• Intranasal examination – anterior
rhinoscopy
• Symptoms of other allergic diseases
• Allergy skin tests and/or
• In vitro specific IgE tests

55. Allergy skin prick testing
Skin prick test / positive result

56. mild
intermittent
mild
persistent
moderate
severe
intermittent
moderate
severe
persistent
avoidance of allergens, irritant and pollutants
immunotherapy
intranasal decongestant (<10 days) or oral decongestant
intranasal steroid
oral or local nonsedative H1-blocker
Management of
Allergic Rhinitis
leukotriene receptor antagonists

57. Oral antihistamines
• First generationFirst generation
agentsagents
Chlorpheniramine
Brompheniramine
Diphenydramine
Promethazine
Tripolidine
Hydroxyzine
Azatadine
• Newer agentsNewer agents
Acrivastine
Azelastine
Cetirizine
Desloratadine
Fexofenadine
Levocetirizine
Loratadine
Mizolastine

58. Nasal antihistamines
• Azelastine
• Levocabastine
• Olopatadine

59. Decongestants: alpha-2
adrenergic agonists
• OralOral
Pseudoephedrine
• NasalNasal
Phenylephrine
Oxymetazoline
Xylometazoline

60. Anti-leukotriene agents
CysLT1 ReceptorCysLT1 Receptor
AntagonistsAntagonists
Montelukast *
Pranlukast *
Zafirlukast
5-Lipoxygenase5-Lipoxygenase
InhibitorsInhibitors
Zileuton
* Approved for allergic rhinitis

61. Nasal corticosteroids
Beclomethasone dipropionate
Budesonide
Ciclesonide*
Flunisolide
Fluticasone propionate
Mometasone furoate
Triamcinolone acetonide
* Currently only approved for asthma

62. Allergen immunotherapy (vaccines)
• Subcutaneous
• Sublingual
• Nasal