11/3- Pediatric Allergic Disease Flashcards
What is another name for atopic dermatitis?
Eczema
What is the “Atopic (Allergic) March”?
The typical progression of allergic diseases that begin early in childhood
- Atopic dermatitis (eczema) (birth+)
- Food allergy
- Allergic rhinitis (3-5 yo)
- Asthma
What is atopic dermatitis?
- Genetic component
- Prevalence
Chronic, inflammatory skin disease
- Involves a genetic defect in the proteins supporting the epidermal barrier
- Relapsing, itchy skin condition
- Affects 15-20% of children
- Also known as “eczema” or “atopic eczema”
Describe the natural history of atopic dermatitis?
- Onset
- Progression
Onset
- 60% in 1st yr
- 85% before 5 yo
Remission
- 70% before adolescence
IgE sensitization
- Only 50% of children < 2 yo
- 80% of older children and adults
T/F: there is a genetic predisposition to atopic dermatitis?
True
What are major genetic components/mutations contributing to atopic dermatitis?
Filaggrin mutations
- Atopic dermatitis
- Allergic asthma
- Peanut allergy
What are causes of the following clinical features?
What are consequences of these causes?
What is seen here?
Ichthyosis
What is seen here?
Excoriation/lichenification
Secondary infection may also occur with atopic dermatitis/eczema. List some of these:
- Bacterial
- Viral
- Mycotic
Bacterial
- Impetiginization
- Polyclonal activation of T-lymphocytes by bacterial exotoxins
Viral
- Localize: human papilloma, molluscum, herpes
- Systemic: eczema herpeticum
Mycotic
- Malassezia
- Dermatophytes, candida
What are some trigger factors of atopic dermatitis?
- Irritants (wool, detergents, disinfectants, cosmetics)
- Microbial agents (Staph aureus, other bacteria, Malassezia furfur, viral infxns)
- Emotional (stress)
- Food allergens (cow’s milk, wheat, egg, soy)
- Aeroallergens (house dust mite, animal dander, tree and grass pollen, mold/fungal allergies)
What are the basic principles of therapy with atopic dermatitis?
Recall AD is associated with:
- Epidermal barrier dysfunction
- Immunological dysregulation
Long-term management involves
- Moistures for skin hydration
- Anti-inflammatory medication
- Flare prevention by avoidance of proven allergens
For the most severe cases, may use cyclosporin or UV therapy, but the mainstay of treatment are anti-inflammatories and moisturizers
What is the definition of a food allergy?
FA is an adverse health effect arising from a specific immune response that occurs reproducibly upon exposure to a given food
Two important points:
- FA is defined as an adverse health effect, not simply having a positive skin prick test or elevated IgE (need hives, vomiting, diarrhea…)
- FA arises from a specific immune response, thus distinguishing it from food intolerance
What are common food allergens?
Proteins or glycoproteins (not fat or carbs)
- Generally heat resistant, acid stable
Major allergenic foods (>85% of food allergies):
- Children: mlik, egg, soy, wheat, peanut, tree nuts
- Adults: peanut, tree nuts, shellfish, fish, fruits, and vegetables
What is the prevalence of food allergies?
- Adults vs. kids
- Prevalence higher in what populations
- Prevalence increasing or decreasing
- Public perception: 20-25%
- Confirmed allergy (oral challenge)
- Adults: 2-3.5%
- Infants/children: 6-8%
- Specific allergens depend upon societal eating and cooking patterns
- Prevalence is higher in those with:
- Atopic dermatitis
- Certain pollen allergies
- Latex allergies
- Prevalence seems to be increasing
What are the immune mechanisms behind food allergies?
- Protein digestion, antigen processing, and some Ag enters blood
- APC is responsible for non-IgE mediated reactions (delayed)
- TNF-a and IL-5
- Activates T cell and B cell to produce IgE
- IgE binds mast cell and causes release of histamine
What are signs/symptoms of IgE and non-IgE allergic reactions?
IgE (acute):
- Skin: urticaria, angioedema, atopic dermatitis
- Respiratory: throat tightness, asthma
- Gut: vomit, diarrhea, pain
- Anaphylaxis
Non-IgE (chronic):
- Atopic dermatitis
- Gut: vomit, diarrhea, pain
What is the #1 cause of anaphylaxis in the ED?
Food allergies
What is food-induced anaphylaxis?
- # 1 cause of anaphylaxis in the ED
- Rapid-onset, up to 30% biphasic
- May be localized (single organ) or generalized
- Potentially fatal
- Any food, highest risk: peanut, tree nut, seafood (cow’s milk and egg in young children)
What is the natural history of food allergies?
- Dependent on food and immunopathogenesis
- ~ 85% of cases of cow milk, soy, egg and wheat allergy remit by age 3 yrs
- Declining/low levels of specific-IgE predictive
- IgE binding to conformational epitopes predictive
- Non-IgE-mediated GI allergy
- Infant forms resolve in 1-3 years
- Toddler / adult forms more persistent
What is the process for evaluating and diagnosing a food allergy?
History: most important
- Sx, timing, reproducibility, treatment, and outcome
- Concurrent exercise, NSAIDs, EtOH
Diet details/symptom diary
- Subject to recall
- “Hidden” ingredient(s) may be overlooked
Physical exam: assess for other allergic and alternative disorders
Identify general mechanism
- Allergy vs. intolerance
- IgE vs. non-IgE mediated
IF YOU SUSEPCT:
- IgE mediated:
- Skin prick tests
- In vitro tests for food-specific IgE
- non-IgE mediated:
- Consider biopsy of gut, skin
- non-immune, (possibly just intolerance) consider:
- Breath hydrogen
- Sweat test
- Endoscopy
How do you manage a food allergy?
- Complete avoidance of specific food trigger
- Ensure nutritional needs are being met
- Education
- Anaphylaxis emergency action plan if applicable
- Most accidental exposures occur away from home
What is emergency treatment of anaphylaxis?
Epinephrine is the drug of choice
- Self-administered Epi is readily available at all times
- If administered, seek medical care IMMEDIATELY
- Train patients, parents, contacts: indications/technique
Antihistamines are secondary therapy only
- WILL NOT STOP anaphylaxis
Written Anaphylaxis Emergency Action Plan
- Schools, spouses, caregivers mature sibs/friends
- Emergency identification bracelet
What is rhinitis?
Symptomatic disorder of the nose characterized by itching, nasal discharge, sneezing and nasal airway obstruction
What is allergic rhinits?
Induction of rhinitis symptoms after allergen exposure by an IgE-mediated immune reaction; accompanied by inflammation of the nasal mucosa and nasal airway hyperreactivity
- Recall, rhinits symptoms include: itching, nasal discharge, sneezing, and nasal airway obstruction
What are clinical manifestations of allergic rhinitis?
- Repetitive sneezing
- Rhinorrhea
- Nasal congestion/ obstruction
- Nasal itching
- Throat clearing
- Postnasal drip, cough, irritability and fatigue
- Symptoms of other co-morbidities
What are co-morbidities of allergic rhinitis?
- Conjunctivitis (itching, tearing, burning of eyes)
- Sinusitis
- Otitis Media
- Cough
- Asthma
How can allergic rhinitis be classified?
Intermittent (seasonal):
- Symptoms under 4 days/wk or
- Symptoms under 4 wks
Persistent:
- Symptoms >4 days/wk or
- Symptoms > 4 wks
ALSO
Mild
- Normal sleep
- Normal daily activities (including sports)
- Normal work-school activities
- No severe Sx
Moderate-Severe
- Disturbed sleep
- Restricted daily activities
- Disrupted work/school activities
- Do have severe Sx
What are globally important sources of allergens?
- House dust mites
- Pets
- Cockroaches
- Molds
- Grass, tree, and weed pollen (seen a little later, ages 4-5 yo, because you need a couple exposures/seasons to develop; internal allergens seen earlier)
How is allergic rhinitis diagnosed?
- Detailed personal and family allergic history
- Intranasal examination – anterior rhinoscopy
- More pale, bluish, inflamed mucosa
- Symptoms of other allergic diseases
- Allergy skin prick tests and/or
- In vitro specific IgE tests
What is shown here?
Allergy skin prick testing
- Right shows positive result
How do in vitro IgE assays work?
- Primary Ab measures specific IgE to different things
How should allergic rhinitis be managed?
DEPENDS ON SEVERITY:
Mild intermittent:
- Oral/local nonsedative antihistamines (H1 blocker)
- Intranasal decongestant (under 10 days) or oral decongenstant
- Leukotriene receptor antagonist
- Avoidance of allergens, irritant, and pollutants
Moderate/severe intermittent:
- All of the above
- Add intranasal steroid
- Possibly add immunotherapy (allergy shots)
Persistent (mild, moderate, severe)
- All of the above
- Immunotherapy (allergy shots)
Describe allergen immunotherapy in children
- Effective and well-tolerated in children
- Prevents new onset of allergen sensitivities in monosensitized pts
- Prevents progression from allergic rhinitis to asthma
- Should be considered with pharmacotherapy and allergen avoidance in the mgmt of children with allergic rhinitis/conjunctivitis, allergic asthma and stinging insect hypersensitivity
What is asthma?
Chronic inflammatory lung disease characterized by:
- Symptoms of cough, wheezing, dyspnea and chest tightness
- Symptoms occur in paroxysms and are usually related to specific triggers
- Airway narrowing is partially or completely reversible
- Increased airways responsiveness to a variety of stimuli
What are the 3 defining components of asthmatic airflow obstruction?
- Airway inflammation
- Reversible airflow obstruction
- Airway hyperresponsiveness
What are the major symptoms of asthma?
- Describe the timing/aggravating factors of symptoms
- Wheezing (during cold/other illness, when laughing/crying, in response to allergens/irritants)
- Breathlessness
- Chest tightness
- Cough (frequent, especially at night; may be only sign in kids; when laughing/crying; in response to allergens/irritants)
- Likely to occur at night and early in the morning
- Likely to increase with activity and exercise (especially in cold weather)
What are precipitating factors/triggers of asthma?
- Allergens: pollens, animals, molds
- Respiratory infections : viruses (mostly)
- Irritants : cigarette smoke, odors, occupational exposures, chemicals, ozone, sulfites, sulfur dioxide
- Exercise
- Upper airway inflammation: sinusitis, rhinitis
- Meteorologic factors: humidity, barometric pressure change, temperature, wind, cold air
- Gastroesophageal reflux
How is asthma diagnosed?
- History of episodic or chronic symptoms of airflow obstruction
- Spirometry or Pulmonary Function Testing (in children >5 years of age)
- Other studies:
- Bronchoprovocation testing (methacholine, exercise)
- Chest X-ray
- Sweat chloride
- Allergy testing
Describe spirometry and especially, it’s findings in an obstructive airway disease (like asthma)
- What does spirometry measure
- How is airflow obstruction defined in spirometry?
- Spirometry helps assess severity of airflow obstruction and aids in the DDx of asthma
- Obstructive vs. restrictive airway dz
- Reversibility of airflow obstruction
- Spirometry measurements include:
- Forced vital capacity (FVC)
- Forced expiratory volume in 1 s (FEV1)
- Airflow obstruction is defined as:
- FEV1 < 80% predicted and
- FEV1/FVC < 85%
T/F: It is essential to classify the severity of an asthmatic patient
True!
- It determines their method of treatment
How is asthma classified (children 5-11 yo)?
Intermittent
Persistent
- Mild
- Moderate
- Severe
Describe an intermittent asthmatic
- Sx 2 or less days/wk
- Nighttime awakenings < 2/mo
- Short acting B2 agonist used < 2 days/wk
- No interference with normal activity
- Normal FEV1 between exacerbations and FEV1 > 80%; FEV1/FVC > 85%
Describe a mild persistent asthmatic
- Sx > 2 days/wk
- Nighttime awakenings 3-4/mo
- Short acting B2 agonist used > 2 days/wk
- Minor limitation of normal activity
- FEV1 < 80% but FEV1/FVC > 80%
Describe a moderate persistent asthmatic
- Sx daily
- Nighttime awakenings >1/wk (but not nightly)
- Short acting B2 agonist used daily
- Some limitation of normal activity
- FEV1 > 60% but < 80%; FEV1/FVC 75-80%
Describe a severe persistent asthmatic
- Sx throughout the day
- Nighttime awakenings often; 7/wk
- Short acting B2 agonist used several times/day
- Extremely limited normal activity
- FEV1 < 60%; FEV1/FVC < 75%
In addition to the intermittent/persistent classifications, how else must a patient’s asthma be classified?
- Well-controlled
- Not well-controlled
- Very poorly controlled
What are the main components of asthma management?
Initial Assessment and Continuous Monitoring
- Monitor symptoms, exacerbations, quality of life
- Periodic pulmonary function tests
Control of Triggers
- Cigarette smoke
- Irritants (at work or at home)
- Air Pollutants
- Allergens
- Rx of diseases exacerbating diseases: GERD, allergic rhinitis, sinusitis
Pharmacotherapy Asthma Education
What are long-term control and quick relief pharmacotherapy agents?
Long-term control:
- Inhaled Corticosteroids
- Cromolyn/nedocromil
- Leukotriene modifiers
- Long-acting beta2-agonists
- Methylxanthines
Quick relief:
- Short-acting inhaled beta2-agonists
- Anticholinergics
- Systemic corticosteroids
