Children experience an average of 6–8 respiratory illnesses per year in early childhood as the immune system develops. Most common childhood illnesses are self-limited viral infections managed with supportive care. Recognition of concerning signs is essential for timely intervention.

Common childhood illnesses include respiratory infections, gastrointestinal infections, fever, and vaccine-preventable diseases. Source: Unsplash.

Fever in Children

Fever is a normal physiological response to infection, not a disease itself. Most fevers in children are caused by self-limited viral infections. The degree of fever does not correlate perfectly with illness severity — a child’s overall appearance and behavior matter more than the temperature number.

Definition. Rectal temperature >100.4°F (38°C). Axillary, oral, and tympanic measurements are acceptable alternatives. Temporal artery thermometers are convenient but less accurate.

Management. Fever in a well-appearing child over 3 months old does not require specific treatment beyond comfort measures. Antipyretics (acetaminophen 10–15 mg/kg every 4–6 hours, or ibuprofen 5–10 mg/kg every 6–8 hours) are used for discomfort — not for achieving a specific temperature. Avoid aspirin in children (Reye syndrome risk). Encourage fluids to prevent dehydration. Do not use cold baths or alcohol rubs.

When to seek emergency care. Fever in an infant <3 months old (requires urgent evaluation due to risk of serious bacterial infection). Fever >104°F (40°C) with lethargy, irritability, or stiff neck. Fever lasting >5 days (Kawasaki disease? urinary tract infection?). Fever with petechial or purpuric rash. Febrile seizure — generalized tonic-clonic seizure lasting <15 minutes, typically in children 6 months to 5 years. Simple febrile seizures do not require anticonvulsant therapy.

⚠ Clinical Correlation

Infants under 3 months with fever require urgent evaluation due to the risk of serious bacterial infection (SBI): urinary tract infection (most common), bacteremia, meningitis, and pneumonia. The Rochester criteria assess low-risk infants: full-term, no perinatal antibiotics, previously healthy, nontoxic appearance, WBC 5,000–15,000, absolute band count <1,500, normal urinalysis and CSF (if indicated). Low-risk infants may be managed as outpatients without antibiotics. High-risk or ill-appearing infants receive full septic workup (CBC, blood culture, urine culture, lumbar puncture, chest X-ray) and empiric antibiotics (ampicillin + cefotaxime or gentamicin) while awaiting culture results.

Upper Respiratory Infections

Baby with upper respiratory infection — Upper respiratory infections are the most common reason for pediatric office visits. Source: Unsplash.

The common cold. Rhinoviruses, adenoviruses, coronaviruses, enteroviruses, RSV, and parainfluenza cause the typical constellation of nasal congestion, rhinorrhea, sneezing, sore throat, and cough. Treatment is supportive: nasal saline drops, bulb suction for infants, cool-mist humidifier, honey (for children over 1 year) for cough, and adequate fluids. Antibiotics do not help. Cough and cold medications are not recommended for children under 6 years.

Otitis media. Acute otitis media presents with ear pain, fever, irritability, and bulging tympanic membrane. Most cases resolve without antibiotics; watchful waiting for 48–72 hours is appropriate for children over 6 months with non-severe illness. Amoxicillin (80–90 mg/kg/day for 10 days) is first-line when antibiotics are indicated.

Pharyngitis. Most pharyngitis is viral (adenovirus, EBV, enterovirus). Group A streptococcal pharyngitis (strep throat) requires antibiotic treatment (penicillin or amoxicillin for 10 days) to prevent acute rheumatic fever. The Centor criteria guide testing: fever, tonsillar exudate, tender anterior cervical lymphadenopathy, and absence of cough.

Gastroenteritis

Acute gastroenteritis causes vomiting and diarrhea, most commonly from rotavirus (now reduced by vaccination), norovirus, and enteroviruses. The primary treatment is rehydration: oral rehydration solution (ORS) for mild to moderate dehydration; intravenous fluids for severe dehydration. Continue age-appropriate feeding (breastfeeding, formula, or regular food) during illness. Zinc supplementation reduces severity and duration. Antidiarrheal medications (loperamide) are not recommended in children. Signs of dehydration: dry mucous membranes, decreased tears, sunken eyes, decreased urine output, lethargy, and prolonged capillary refill.

Urinary Tract Infections

UTIs in children present with fever, dysuria, frequency, urgency, and abdominal pain. Infants may present with fever alone, poor feeding, or irritability. Diagnosis by urine culture (catheterization or clean-catch specimen). Treatment with age- and resistance-appropriate antibiotics for 7–10 days. Renal and bladder ultrasound after the first febrile UTI in younger children to evaluate for structural abnormalities. Voiding cystourethrogram (VCUG) is indicated for abnormal ultrasound or recurrent febrile UTIs.

Skin Conditions

Diaper dermatitis (diaper rash). Irritant contact dermatitis is managed with frequent diaper changes, barrier creams (zinc oxide), and air exposure. Candidal diaper rash (satellite pustules, beefy red) requires topical antifungal (nystatin, clotrimazole).

Atopic dermatitis (eczema). Chronic pruritic skin condition managed with emollients, topical corticosteroids for flares, and trigger avoidance.

Impetigo. Contagious bacterial skin infection with honey-colored crusts. Topical mupirocin is effective for localized disease; oral antibiotics (cephalexin) for extensive or recurrent cases.

When to Seek Emergency Care

Respiratory distress: tachypnea, retractions, nasal flaring, grunting, stridor, or cyanosis. Altered mental status: lethargy, confusion, unresponsiveness, or stiff neck. Dehydration: sunken eyes, dry mouth, no tears, decreased urine output, or lethargy. Severe pain: persistent crying, inconsolability, or guarding. Trauma: head injury with loss of consciousness, persistent vomiting, or suspected fracture. Poisoning or overdose. Seizure. Severe allergic reaction (anaphylaxis): difficulty breathing, lip or facial swelling, hives, or hypotension.

Summary

Most common childhood illnesses are viral, self-limited, and managed with supportive care. Fever in infants under 3 months requires urgent evaluation. Oral rehydration is the cornerstone of gastroenteritis management. Recognizing acute otitis media, strep pharyngitis, and UTIs guides appropriate antibiotic use. Parents should be educated about signs of serious illness and when to seek emergency care. Antipyretics are for comfort, not for achieving a specific temperature.