History taking allergy and asthma in pediatrics

Asthma

1. Vinay Mehta, M.D.
Allergy & Asthma Associates of Southern
California
Irvine, CA
History-taking in allergy &
immunology

2. Definitions
Allergy
•IgE-mediated hypersensitivity reaction to an
allergen
•The immune system reacts to a substance that is
normally harmless
Atopy
•The genetic tendency to develop allergy
Atopic march
•The natural sequence of allergic manifestations
from childhood to adulthood

3. Definitions
Allergen
•A protein (inhaled, ingested or though direct
contact) of molecular weight 10-70 kdcapable of
triggering an allergic reaction in a sensitized
individual
Sensitization
•Formation of IgE antibodies against a particular
antigen through repeated exposure

4. Allergies can affect individuals in
different ways

5. Allergic disorders
•Allergic rhinitis/conjunctivitis
•Chronic sinusitis
•Asthma
•Atopic dermatitis
•Food allergy
•Urticaria/angioedema
•Drug allergy
•Stinging insect allergy
•Anaphylaxis

6. Atopic march
•Atopy is the genetic tendency to develop allergic
disease
•Atopy tends to be familial
•Atopic march
•Food allergy (0-1 yr)
•Eczema (3 months–3 yrs): “the entry point”
•Asthma (3 yrs–adulthood)
•Allergic rhinitis (7 yrs–adulthood)

7. Atopic march
•Early intervention may prevent further progression in the
atopic march

8. •400 million with allergic rhinitis
•300 million with asthma (38 million in India)
•200 million with food allergies
•Atopic eczema affects 15-20% of children and 3%
of adults worldwide
•250,000 asthma-related deaths annually
Burden of allergic disorders

9. Epidemiology of allergic disorders
Risk factors for atopy
•Positive family history
•Elevated serum IgE
•Sensitization to aeroallergens
•Dust mite, cockroach, Alternaria, and cat are
potentially asthmogenic
•Exposure to cigarette smoke
•Exposure to airborne particulate matter
•Reduced infant gut microbiota diversity (antibiotics)

10. Epidemiology of allergic disorders
•75% of asthmatics develop AR
•40% of AR patients develop asthma
•2/3 of AD patients develop AR
•1/2 of AD patients develop asthma
•1/3 of children with severe AD have food allergies
•Allergy is a systemicimmunologic dysfunction with
local manifestations rather than a set of discrete
autonomous symptoms

11. Allergic rhinitis
•Disorder of the nose induced by IgE-mediated
inflammation after allergen exposure
•SAR –caused by seasonal allergens (e.g. tree,
grass, weed pollen)
•PAR –caused by perennial allergens (e.g. dust mite,
pet dander, cockroach, mold)
•Cardinal symptoms: congestion, rhinorrhea,
sneezing, itching, ocular symptoms
•Secondary symptoms: fatigue, headache,
cognitive impairment, sleep disturbance

12. Allergic rhinitis: signs & symptoms

13. Chronic sinusitis
•Group of disorders characterized by
inflammation of the mucosa of the nose and
paranasal sinuses
•Acute rhinosinusitis is usually related to
infection
•Chronic rhinosinusitis is usually related to
chronic inflammation

14. Chronic sinusitis
•2/4 cardinal symptoms + objective evidence of
sinus mucosal disease (endoscopy or CT)
–Anterior and/or posterior mucopurulent
drainage
–Nasal obstruction
–Facial pain, pressure, and/or fullness
–Decreased sense of smell
•Symptoms do not reliably correlate with objective
findings, nor do they differentiate among subtypes
of CRS

15. Asthma
•Heterogeneous disease characterized by chronic
airway inflammation
•Defined by respiratory symptoms such as wheeze,
shortness of breath, chest tightness and cough that
vary over time and in intensity + variable expiratory
airflow limitation

16. Broncho-
constriction
Airway
inflammation
Bronchial
hyper-
responsiveness
Asthma: cardinal features
Adapted from Bousquet et al. Am J Respir Crit Care Med.2000;161:1720-1745.
before
after Edema
Spirometry
Exhaled
nitric oxide
Methacholine
challenge

17. Asthma: diagnosis
▪Symptoms include wheezing, shortness of breath,
chest tightness and cough.
▪Vary over time in their occurrence, frequency and
intensity
▪Symptoms are caused by expiratory airflow
obstruction due to:
▪Bronchoconstriction
▪Airway wall thickening
▪Increased mucus
▪May be triggered or aggravated by viral infections,
allergens, tobacco smoke, exercise and stress

18. Atopic dermatitis
•Chronic, relapsing, pruritic disease of the skin
•Represents the beginning of the atopic march
•Two to three-fold increase in the past 30 years
•15-20% of children and 3% of adults worldwide are
affected
•Early intervention may help arrest the progression of
the atopic march

19. Food allergy
•The ‘second wave’ of the allergy epidemic
•Prevalence in preschool children in developed
countries is as high as 10%
•Cow’s milk, egg, soy, wheat, peanut, tree nuts, fish,
shellfish, and seeds account for >90%
•Can result in anaphylaxis
•Asthma and food allergy may coexist

20. Urticaria
•Circumscribed, raised erythematous lesions associated
with subcutaneous edema
✓Pruritic
✓Symmetric
✓Pale centres
✓Blanche with pressure
✓Vary in size and shape

21. Symmetry of hives

22. Angioedema
•Well-demarcated edema of the deep layers of the dermis
and subcutaneous tissue
✓Non-pitting
✓Non-dependent
✓Face, lips, extremities, genitals
✓Present in ~40% of patients with chronic urticaria
✓Angioedema withouturticaria should prompt
consideration of bradykinin-mediated angioedema

23. Lip involvement of angioedema

24. Anaphylaxis
•A serious allergic
reaction that is rapid in
onset and may cause
death

25. History-taking
•Taking a good history is critical to making a correct
diagnosis
•It involves determining the symptom complex and
its relationship to allergen exposure
•Do not rely solely on skin test results →only
the history will determine if the results are relevant

26. History-taking
•Onset of symptoms
•Character, duration, frequency, severity of sx
–Localized vs. systemic (eyes, upper airway,
lower airway, GI tract, skin)
–Frequency and severity of sxoften determine
how aggressively to treat
•Temporal relationship
–Seasonal: pollen
–Perennial: dust mite, cockroach, mold, pets

27. History-taking
•Trigger factors: allergens, tobacco smoke, irritants
•Impact of disease on quality of life: school
performance, work performance, activities of daily
living
•Personal history of atopy
•Family history of atopy

28. History-taking
•Pet exposure
•Biomass fuel exposure
•Daycare
•List of medications (prescription and OTC)
•Past medical and surgical history

29. Disease-focused
history-taking pearls

30. Allergic rhinitis
•Primary symptoms: nasal congestion, nasal pruritus,
rhinorrhea, sneezing, post nasal drip, ocular
•Secondary symptoms: fatigue, headache, cognitive
impairment, snoring, sleep disturbance, mood
disturbance
•Onset and duration of symptoms
•Seasonal vs. perennial?
•Response to antihistamine therapy?
•Degree to which symptoms interfere with daily
activities, sleep, sports, leisure, work, school

31. Chronic sinusitis
•Presence of cardinal symptoms:
–Anterior and/or posterior nasal mucopurulent drainage
–Nasal congestion
–Facial pain, pressure, and/or fullness
–Reduction or loss of sense of smell
•Duration of symptoms
•Presence of contributing conditions: AR, smoking
•Previous treatments
•Previous sinus imaging

32. Asthma
▪Symptoms: cough, wheeze, shortness of breath,
chest tightness
•Children
–Fatigue, irritability, chest hurting
–Avoidance of activities
•Infants
–Difficulty eating, grunting during sucking
▪Family history of asthma
▪Comorbidities: allergic rhinitis, chronic sinusitis,
atopic eczema, gastro-esophageal reflux, sleep
apnea

33. Asthma
•Primarily difficulty is breathing out vs. breathing in
•Often worse at night
•Symptoms should respond to bronchodilators
•Identify the triggers: URI, allergens, work-related
exposures, tobacco smoke, exercise, cold air,
irritants
•Assess age at onset of symptoms →helpful in
determining the asthma phenotype

34. Atopic dermatitis
•Atopic dermatitis generally begins in early childhood
•Pruritus is a cardinal symptom
•Does the rash fit the typical pattern and location?
•Is the rash chronic and relapsing?
•Body surface involvement, severity of lesions
•Impact on sleep, activities of daily living, social life
-If severe eczema in children <1 month, consider
immunodeficiency (Hyper-IgEsyndrome, Wiskott-
Aldrich syndrome)

35. Food allergy
•Distinguish between IgE-mediated reactions (i.e.
anaphylaxis) vs. non-IgE-mediated reactions
•Anaphylaxis: hives, angioedema, itchy mouth, itchy
throat, cough, shortness of breath, wheeze, nausea,
vomiting, diarrhea, abdominal pain, flushing,
lightheadedness, feeling of impending doom
•Establish the temporal association between
ingestion of the food and the onset of symptoms (if
>2 hours, IgE-mediated reaction unlikely)
•Is the reaction reproducible eachtime the food is
ingested?

36. Urticaria/angioedema
•Distinguish between acute (<6 weeks) vs. chronic
(>6 weeks)
•Ask about associated signs and symptoms
•Duration of individual lesions (if >24 hrsor leave
bruising →skin biopsy to rule out vasculitis)
•Accompanying angioedema
–angioedema without urticaria may be
bradykinin-mediated (ACE-I induced or HAE)
•Look for clues of a systemic disease (i.e. fever,
arthralgia, myalgia, night sweats, weight loss)

37. Urticaria/angioedema
Aggravating factors
•Physical factors: heat, cold, sweat, friction
•NSAIDs: worsen symptoms in 25% of patients
•Stress: physical or psychologic
•Dietary habits and alcohol: spicy foods and alcohol
tend to aggravate symptoms in some

38. Anaphylaxis
•Symptoms and timing consistent with anaphylaxis?
•Suspected trigger
•Treatment and response
•Associated factors
–Exercise
–Medications
–Food
–Infection
–Alcohol
•ER records (vital signs, physical examination) can
be helpful in cases where symptoms are subjective

39. Immunodeficiency
•Infections
–Frequent, severe, unusual organisms, difficult to treat
–Chronic diarrhea, failure to thrive
–Family history or unexplained early death
–Complication from a live vaccine (i.e. BCG)
•Autoimmune disease
-Thyroiditis, rheumatoid arthritis, hemolytic anemia,
thrombocytopenia, neutropenia, pernicious anemia,
celiac disease, vitiligo
•Malignancy
–Lymphoma

40. *The Jeffrey Modell
Foundation Medical
Advisory Board
10 Warning
Signs of
Immuno-
deficiency*

41. Take home points
•Obtaining a good clinical history is crucial to the
allergist
•Patient history is the basis for selecting appropriate
diagnostic testing (not the opposite!)
•Do not limit your questions to the presenting
complaint or you will miss important information
•Be systematic in your history-taking; go through the
differential diagnosis in your mind as you interact
with the patient