Pediatrics lecture 7

atopy

1. result of complex interaction between multiple genes and environmental factors

2. immunoglobulin (Ig)E- mediated diseases

immunoglobulin (Ig)E- mediated diseases

1. allergic rhinitis

2. asthma

3. food allergy

allergen

antigen that triggers IgE response in genetically predisposed individuals

hypersensitivity disorders

four groups based on mechanism of tissue inflammation

type 1 hypersensitivity rxn

1. interval between exposure and reaction- <30 mins, 2-12 hours

2. IgE

3. target or antigen= pollens, food, venom, drugs

4. mediators= histamine, leukotrienes

5. examples- anaphylaxis, urticaria, allergic rhinitis, allergic asthma

type 2 hypersensitivity rxn

1. interval between exposure and reaction- variable

2. IgM, IgA, IgG

3. target or antigen= RBCs, platelets

4. mediators= complement

5. examples- hemolytic anemia, thrombocytopenia

type 3 hypersensitivity rxn

1. interval between exposure and reaction- 1 to 3 weeks after drug exposure

2. antigen-antibody complexes

3. target or antigen= blood vessels, liver, spleen, kidney, lung

4. mediators= complement, anaphylatoxin

5. examples- serum sickness, hypersensitivity pneumonitis

type 4 hypersensitivity rxn

1. interval between exposure and reaction- 2 to 7 days after drug exposure

2. lymphocytes

3. target or antigen= M. tuberculosis, chemicals

4. mediators= cytokines like TNF-alpha

5. examples- TB skin reaction, contact dermatitis, graft vs host disease

atopic triad

1. asthma

2. atopic dermatitis (eczema)

3. allergic rhinitis

4. eosinophilic esophagitis is recently being included as well

many atopic children have involvement of _____________ body systems.

>1

physical exam findings in atopic triad

1. allergic salute

2. allergic shiners

3. Dennie lines (Dennie-Morgan folds)

4. urticaria

5. keratosis pilaris

6. wheezing

allergic salute

rubbing nose in response to nasal discharge-> transverse nasal crease

initial diagnostic evaluation of the atopic child

1. in vivo skin testing

2. in vitro serum testing

in vivo skin testing

1.. introduces allergen into skin via prick/puncture or intradermal injection

2. must stop antihistamine prior

3. if properly performed- most sensitive method for detecting allergen-specific IgE

in vitro serum testing

1. measures levels of antigen-specific IgE

2. IgE immunoassay

3. best if patient cannot discontinue meds, have extensive dermatitis, or are noncompliant for skin testing

allergic march

describes natural progression of allergic diseases from infancy to adulthood

what are the ages for the steps of the allergic march?

1. step 1- birth to 1 year of age

2. step 2- 1-3 years of age

3. step 3- 4-6 years of age

4. step 4- 5-7 years of age

step 1 of allergic march

skin irritation such as hives or eczema

step 2 of allergic march

1. food allergies

2. peanut, tree nut, cows milk, egg, wheat, soy, fish, shellfish

step 3 of allergic march

seasonal and environmental allergies, including allergic rhinitis

step 4 of allergic march

asthma

allergic rhinitis

1. allergic rhinosinusitis or hay fever

2. type 1 IgE mediated reaction

risk factors for allergic rhinitis

1. family history of atopy

2. personal history of asthma or atopic dermatitis

3. M>F, early use of antibiotics, maternal smoking 1st year of life

allergic shiners

infraorbital edema

Dennie-Morgan lines

accentuated lines or folds below lower lids

physical exam findings of allergic rhinitis

1. allergic shiners, Dennie-Morgan lines, allergic salute

2. allergic facies

3. blue-boggy nasal mucosa

4. cobblestoning

5. Eustachian tube dysfunction

diagnosis of allergic rhinitis

1. usually clinical

2. skin testing- allergist, maybe ENT

3. serum testing- IgE immunoassay

treatment for allergic rhinitis

1. intranasal corticosteroids

2. antihistamine

3. adjunctive treatments

which intranasal steroid for allergic rhinitis if ≥6?

beclomethasone

which intranasal steroid for allergic rhinitis if ≥2?

mometasone furoate or fluticasone furoate

which intranasal steroid for allergic rhinitis if ≥4?

fluticasone proprionate

nonsedating antihistamines for allergic rhinitis

1. loratadine- ≥2 y/o

2. fexofenadine- ≥2 y/o

minimally sedating antihistamines for allergic rhinitis

cetirizine- ≥6 months

sedating antihistamines for allergic rhinitis

1. AVOID

2. brompheniramine, chlorpheniramine, clemastine

nasal spray antihistamines for allergic rhinitis

1. azelastine ≥6 y/o

2. olopatadine ≥6 y/o

what are adjunctive treatments used for allergic rhinitis?

1. Montelukast if ≥6 months

2. reduce allergen exposure

3. immunotherapy (allergist)

referral for allergic rhinitis?

1. if severe or refractory

2. allergist, pulmonology, ENT

complications of allergic rhinitis

1. chronic cough

2. eustachian tube dysfunction, otitis media

3. rhinosinusitis

4. tonsillar and adenoid hypertrophy

prevention of allergic rhinitis

1. avoid allergen exposure

2. breastfeeding may have protective effect

3. early exposure to animals may have protective effect

4. avoid smoke exposure

atopic dermatitis is NOT...

a type 1 allergy and is NOT associated with allergic sensitization

risk factors for atopic dermatitis

1. family history of atopy

2. abnormal skin barrier function

clinical presentation of atopic dermatitis

dry skin and severe pruritus

where does eczema usually present on the body?

1. infants- face, scalp, extensor surfaces of extremities

2. children- antecubital and popliteal fossae

3. adolescents- flexural surfaces

non-pharm treatment for atopic dermatitis

1. restore skin barrier- petroleum

2. eliminate exacerbating factors- hot baths, overheating/sweating, hard water, fragrant detergents, etc

pharm treatment for mild to moderate atopic dermatitis

1. topical corticosteroid

2. mild- hydrocortisone 2.5% cream

3. moderate- triamcinolone 0.1% cream

treatment for moderate to severe atopic dermatitis

if no response to topical steroids, consider biologics like dupilumab (Dupixent)

referral for atopic derm

allergist or dermatology

when is a referral for atopic derm indicated?

1. diagnosis uncertain

2. inadequate response to topical therapy

3. involvement of face or skin folds and considering high potency steroid

4. phototherapy

5. immunotherapy- allergist

what may provide protective effect against atopic dermatitis?

breastfeeding

most common food allergies in children

1. cow's milk, eggs

2. peanuts and tree nuts

3. soy

4. wheat

5. fish and shellfish

etiology of food allergies in children

type 1 IgE mediated reaction- most common

risk factors for food allergies

1. family history of atopy

2. eczema

3. delayed introduction to foods

IgE mediated food allergy

1. symptoms rapidly after ingestion

2. symptoms to one or more organ systems

non-Ige mediated allergy

1. subacute or chronic symptoms

2. normally isolated to GI tract or skin

diagnosis of food allergies

1. history

2. skin testing

3. IgE serum immunoassay

4. oral food challenges

treatment for food allergies

1. strict avoidance

2. assess need for epi pen

3. allergy action plan

4. antihistamine or inhaled beta agonist if asthma

epi pen prescription

1. 0.3 mg dose if ≥25 kg

2. epi pen jr- 0.15 mg dose, <25 kg

3. dispense 2 pens

preventing food allergies

1. high risk children who have not shown signs- breastfeeding

2. introduction of solids between 4-6 months

3. early introduction of peanuts

if a baby has mild eczema, where should peanuts be introduced?

at home

if a baby has severe eczema, when should peanuts be introduced?

after allergy testing has been done

common drug allergy in children

1. penicillin

2. IgE mediated drug reaction

what does NOT predispose a patient to developing a drug reaction?

history of atopy

immediate reaction to a medication

1. anaphylaxis

2. likely IgE mediated

3. itching, urticaria, angioedema, bronchospasm, laryngeal edema, abdominal distress, hypotension

delayed drug reaction

1. rash- maculopapular (morbilliform)

2. red macules or papules- FIXED lesions

3. delayed urticarial reaction- intense itching, red plaques

diagnosis of drug allergy

1. history

2. skin testing

3. if skin testing negative-> oral challenge

referral for drug allergy

allergist

treatment for symptoms of drug allergy

1. PO antihistamine or PO steroid if severe itching

2. avoid offending drug

3. desensitization

if a patient has an allergy to penicillins, what other med class may they also be allergic to due to cross reactivity?

cephalosporins

sudden infant death syndrome (SIDS)

1. unexpected death of infant (<12 mo) where cause remains unexplained

2. peaks at 2-4 months

leading cause of infant mortality between 1 month and 1 year in U.S.?

SIDS

prevention of SIDS

1. back to sleep, avoid soft bedding

2. smoking cessation

3. breastfeeding

4. pacifier use and sharing a room in separate beds

laryngomalacia

1. collapse of supraglottic structures during inspiration

2. due to decreased muscle tone of larynx and surrounding structures or to immature cartilaginous structures

most common cause of stridor in infants?

laryngomalacia

when does laryngomalacia peak and resolve?

1. peaks at 4-8 months

2. resolves at 12-18 months

clinical presentation of laryngomalacia

1. "wet" inspiratory stridor loudest during feeding or when active

2. exacerbated by upper airway inflammation- URI, GERD

3. little or no expiratory component

diagnosis of laryngomalacia

1. usually clinical

2. severe- refer to ENT for nasopharyngoscopy

MCC of obstructive sleep apnea in children?

adenotonsillar hypertrophy

risk factors for OSA

1. T21

2. craniofacial abnormalities

3. obesity

clinical presentation of OSA in children

1. enlarged tonsils

2. restless sleep +/- snoring

3. inattention/ hyperactivity

4. poor somatic growth

workup/diagnosis in OSA

1. refer to otolaryngology

2. PSG- polysomnogram

what is the onlt definitive test for OSA?

polysomnogram

treatment for OSA?

1. adenoidectomy +/- tonsillectomy may be curative

2. if no surgery needed- CPAP or BiPAP

foreign body aspiration

1. most common if <3 y/o

2. right mainstem bronchus most often affected

which foods are children likely to choke on?

nuts, hotdogs, grapes, popcorn

clinical presentation of FB aspiration- complete obstruction

1. severe resp. distress, cyanosis and AMS

2. emergency

clinical presentation of FB aspiration- partial obstruction

1. cough, wheezing, diminished breath sounds

2. tachypnea and stridor

treatment for FB aspiration

rigid bronchoscopy

cystic fibrosis

1. autosomal recessive disorder

2. CFTR- cystic fibrosis transmembrane conductance regulator

3. deranged chloride transport- thick, viscous secretions in lungs, pancreas, liver, intestine, reproductive tract

clinical presentation of cystic fibrosis

meconium ileus, respiratory symptoms and FTT

when should workup for cystic fibrosis be performed?

1. positive newborn screen

2. findings suggestive of CF

3. ALL siblings of patients with CF

findings suggestive of CF

1. meconium ileus

2. FTT, jaundice, electrolyte abnormalities

3. GI or resp. symptoms

4. digital clubbing

5. nasal polyps <12 y/o

diagnosis of CF

1. routine newborn screen

2. sweat chloride test- test of choice

3. DNA analysis- CFTR sequencing

referral for CF?

pulmonology and CF center

treatment for CF?

1. no cure

2. keep airway clear- chest physiotherapy

3. nebs- decrease mucus viscosity

4. antibiotics- pulm. exacerbations

5. precision therapies

6. pancreatic enzyme capsules, high calorie diet

what bacteria often infect patients with CF?

P. aeruginosa and S. aureus

asthma

1. type 1 IgE mediated reaction

2. airway hyperresponsiveness and edema

3. chronic inflammation leads to airway remodeling- irreversible structural changes and progressive loss of pulmonary function

strongest risk factor for development of asthma?

atopy

other risk factors for asthma

1. exposure to smoke

2. M>F before puberty

3. F>M after puberty

clinical manifestations of asthma

1. classic- intermittent dyspnea, cough, wheezing

2. exercise intolerance

3. nocturnal symptoms common

asthma triggers

1. changes ins easons- allergens, weather

2. URIs

3. exercise

4. irritants

5. emotions/stress

6. GERD