Common Childhood Illnesses: Ear Infections, Strep Throat, RSV, Croup, and Viral Exanthems

Introduction

Children experience an average of 6-8 respiratory infections per year (more in daycare). While most are self-limited viral illnesses, accurate diagnosis distinguishes conditions requiring specific treatment (bacterial infections) from those requiring supportive care only. Recognition of serious illness (sepsis, meningitis, pneumonia) is essential.

Otitis Media (Middle Ear Infection)

Classification

Type	Duration	Features
Acute otitis media (AOM)	<3 weeks	Acute onset, middle ear effusion + signs of acute infection
Otitis media with effusion (OME)	Variable	Middle ear fluid without acute infection
Chronic suppurative otitis media (CSOM)	>6 weeks	Persistent purulent drainage through tympanic membrane perforation
Recurrent AOM	3+ episodes in 6 months or 4+ in 12 months	Separate episodes with resolution between

Diagnosis of AOM

Criteria	Finding
Acute onset	Abrupt onset of ear pain or fever
Middle ear effusion	Bulging tympanic membrane, decreased mobility, otorrhea
Signs of inflammation	Erythema, bulging, otalgia

Pathogens

Pathogen	Percentage	Notes
Streptococcus pneumoniae	25-35%	Most common; pneumococcal vaccine effective
Non-typeable Haemophilus influenzae	25-30%	Increasing beta-lactamase production
Moraxella catarrhalis	10-15%	Beta-lactamase producing (all)
Group A Streptococcus	3-5%
Viruses (RSV, influenza, rhinovirus)	15-20%	Often precede or coexist with bacterial AOM

Treatment

Age/Severity	Antibiotic	Dose	Duration
<6 months (all)	Amoxicillin 90 mg/kg/day divided BID	10 days
6-24 months (severe or bilateral)	Amoxicillin	90 mg/kg/day divided BID	10 days
6-24 months (non-severe, unilateral)	Watchful waiting or amoxicillin	90 mg/kg/day divided BID	10 days
>24 months (non-severe)	Watchful waiting or amoxicillin	90 mg/kg/day divided BID	5-7 days
Severe illness or treatment failure	Amoxicillin-clavulanate (Augmentin ES)	90 mg/kg/day amoxicillin component	10 days
Penicillin allergy (non-type I)	Cefdinir, cefpodoxime, cefuroxime	Per package	5-10 days
Penicillin allergy (type I)	Azithromycin or clindamycin

Streptococcal Pharyngitis (Strep Throat)

Epidemiology

Aspect	Data
Age peak	5-15 years
Season	Late winter, early spring
Incidence	15-30% of pharyngitis in children (higher in school-age)
<3 years	Uncommon (10% of pharyngitis, often mild)
Mode	Respiratory droplets, close contact

Clinical Features

Feature	Suggestive of GAS	Suggestive of Viral
Fever	>100.4F (38C)	Low-grade or absent
Sore throat	Sudden onset, severe (dysphagia)	Gradual onset
Tonsillar exudate	Present (may be white/yellow)	Often absent
Cervical LAD	Tender, anterior	Diffuse
Cough	Absent	Often present
Rhinorrhea	Absent	Often present
Hoarseness	Absent	Often present
Conjunctivitis	Absent	May be present
Diarrhea	Absent	May be present

Modified Centor Criteria (McIsaac Score)

Criteria	Points
Temperature >100.4F (38C)	1
Absence of cough	1
Tonsillar exudate/swelling	1
Tender anterior cervical LAD	1
Age <15	0
Age 15-44	-1
Age >45	-1

Score	Risk of GAS	Action
-1 to 0	1-2%	No testing or antibiotics
1	5-10%	No testing or antibiotics (or rapid test if uncertainty)
2	15-20%	Rapid test + culture if negative
3	30-40%	Rapid test + culture if negative
4	50-60%	Rapid test + culture if negative

Treatment

Regimen	Dose	Duration	Notes
Amoxicillin	50 mg/kg once daily (max 1 g)	10 days	Better tasting; once daily
Penicillin VK	250 mg BID-TID (child <27 kg); 500 mg BID-TID (adult)	10 days	Narrow spectrum
Amoxicillin-clavulanate	Per amoxicillin dose	10 days	If concern for amoxicillin failure
Cephalexin (if non-anaphylactic penicillin allergy)	20-40 mg/kg/day divided BID	10 days	Cross-reaction risk low
Clindamycin (if anaphylactic penicillin allergy)	20 mg/kg/day divided TID	10 days
Azithromycin (if cannot tolerate others)	12 mg/kg once daily	5 days	Increasing resistance

RSV and Bronchiolitis

Pathophysiology

Aspect	Detail
Pathogen	Respiratory syncytial virus (RSV), subtypes A and B
Season	November - March (peak January-February)
Age	Most severe in infants <12 months (peak 2-6 months)
Transmission	Respiratory droplets + fomites; survives hours on surfaces
Incubation	4-6 days
Mechanism	Viral invasion of bronchiolar epithelium leads to necrosis, inflammation, edema, mucus plugging
Immunity	Incomplete; reinfection common throughout life

Clinical Course

Day	Phase	Symptoms
0-2	Upper respiratory	Rhinorrhea, congestion, cough (may have low-grade fever)
3-5	Lower respiratory (bronchiolitis)	Tachypnea, retractions, wheezing, crackles, nasal flaring, grunting, hypoxia
5-7	Recovery	Gradual improvement of respiratory symptoms
10-14	Full recovery	Cough may persist 2-3 weeks

Severity Assessment

Finding	Mild	Moderate	Severe
Respiratory rate	<60/min	60-70/min	>70/min
Oxygen saturation	>95%	90-95%	<90%
Retractions	Mild intercostal	Moderate (intercostal + subcostal)	Severe (with nasal flaring, head bobbing)
Feeding	Normal	Decreased	Unable to feed
Apnea	None	Possible	Present

Treatment (Supportive Care)

Intervention	Recommendation
Oxygen	If SpO2 persistently <90-92%
Nasal suctioning	Deep suctioning (bulb syringe, nasal aspirator)
Hydration	IV fluids/NG if unable to feed
Bronchodilators	Do NOT routinely use (albuterol, epinephrine: no proven benefit)
Corticosteroids	Do NOT use (no evidence)
Ribavirin	Reserved for immunocompromised/ severe cases
Chest physiotherapy	Not recommended
Antibiotics	Only if secondary bacterial infection

High-Risk Infants (Consider RSV Prophylaxis - Palivizumab/Synagis)

Risk Factor	Criterion
Prematurity	<29 weeks gestational age (season)
Congenital heart disease	Hemodynamically significant
Chronic lung disease	<32 weeks + oxygen requirement at 36 weeks PMA
Immunodeficiency	Severe combined immunodeficiency, transplant

Croup (Laryngotracheobronchitis)

Aspect	Detail
Pathogens	Parainfluenza (most common), RSV, influenza, adenovirus, measles
Age peak	6 months - 3 years
Season	Fall, early winter
Pathophysiology	Subglottic inflammation and edema causes upper airway obstruction
Classic presentation	Barking cough (“seal-like”), stridor (inspiratory), hoarseness, worse at night
Westley Croup Score	Assess severity (mild/moderate/severe/impending respiratory failure)

Severity and Management

Severity	Stridor	Retractions	Air Entry	O2 Sat	Management
Mild	Only with agitation	None to mild	Normal	>95%	Single dose of dexamethasone 0.15 mg/kg PO; supportive; outpatient
Moderate	At rest	Intercostal, suprasternal	Decreased	92-95%	Dexamethasone 0.15-0.6 mg/kg PO/IM/IV; racemic epinephrine (2.25% 0.5 mL neb) or L-epinephrine (1:1000 5 mL neb); observe 2-4 hours after epinephrine
Severe	At rest, biphasic	Severe, may have head bobbing	Significantly decreased	<92%	Dexamethasone + racemic epinephrine; admit; consider heliox, CPAP
Impending failure	Fatigue, decreased consciousness	Decreasing retractions (paradoxical)	Minimal	<90%	ICU; consider intubation

Hand-Foot-Mouth Disease (HFMD)

Aspect	Detail
Pathogen	Coxsackievirus A16 (most common), Enterovirus 71 (severe), other enteroviruses
Age peak	<5 years (but can affect all ages)
Incubation	3-6 days
Season	Summer, early fall
Spread	Fecal-oral, respiratory droplets, contact with vesicle fluid
Duration	7-10 days

Clinical Features

Phase	Findings
Prodrome (1-2 days)	Fever, malaise, sore throat, decreased appetite
Rash (days 1-2)	Maculopapular or vesicular rash on hands (palms), feet (soles), and mouth (tongue, buccal mucosa, palate)
Oral lesions	Painful vesicles that ulcerate (may interfere with eating/drinking)
Skin lesions	Small, oval, gray vesicles with erythematous base; non-pruritic
Atypical presentations	Eczema coxsackium (in children with eczema); onychomadesis (nail shedding weeks later)

Management

Aspect	Treatment
Symptomatic relief	Acetaminophen/ibuprofen for fever/pain; oral analgesics (lidocaine mouthwash)
Hydration	Encourage fluids (cold, non-acidic); popsicles; monitor for dehydration
No antibiotics	Viral illness; no specific antiviral
Contagious	Most contagious during first week; virus can shed for weeks
School exclusion	Until fever resolves and vesicles are dry (typically 5-7 days)

Roseola (Exanthem Subitum / Sixth Disease)

Aspect	Detail
Pathogen	Human herpesvirus 6 (HHV-6) most common; HHV-7 less common
Age peak	6-24 months (90% by age 2)
Incubation	9-10 days
Season	Year-round (spring/fall slight increase)
Transmission	Respiratory droplets, saliva

Phase	Duration	Symptoms
Febrile phase	3-5 days	High fever (103-105F / 39-41C); child appears well despite fever; febrile seizures possible (10-15%)
Defervescence + rash	1-2 days	Fever drops suddenly; pink maculopapular rash appears (trunk first, spreads to extremities)
Rash	1-2 days	Blanching, rose-pink macules/papules; begins on trunk; non-pruritic
Recovery	1-3 days	Rash fades; no desquamation

Fifth Disease (Erythema Infectiosum)

Aspect	Detail
Pathogen	Parvovirus B19
Age peak	5-15 years
Incubation	4-14 days
Season	Winter, spring
Transmission	Respiratory droplets; also vertical (to fetus) and blood-borne

Clinical Phases

Phase	Duration	Findings
Prodrome (non-specific)	2-3 days	Low-grade fever, headache, coryza (may be absent)
Slapped cheek rash (phase 1)	2-4 days	Bright red, confluent macules on cheeks (slapped cheek); circumoral pallor
Reticular rash (phase 2)	1-3 weeks	Lacy, reticular maculopapular rash on trunk, arms, buttocks; may wax and wane with heat, sun, exercise, stress
Recovery	Variable	Rash may recur for weeks; no scarring

Complications

Complication	Affected Population
Aplastic crisis	Patients with hemolytic anemias (sickle cell, spherocytosis)
Chronic pure red cell aplasia	Immunocompromised (HIV, transplant, chemotherapy)
Hydrops fetalis	Pregnant women (infection in first 20 weeks)
Arthritis/arthralgia	More common in adult women (50%)