Management of Pertussis in Infants

Antibiotic Management

The Centers for Disease Control and Prevention (CDC) recommends continuing azithromycin at 10 mg/kg/day for the full 5-day course as the first-line treatment for infants under 6 months with pertussis, focusing on supportive care since antibiotics will not alter the clinical course of established paroxysmal coughing 1, 2
The current azithromycin regimen is correct: 10 mg/kg per day for 5 days is the CDC-recommended dosing for infants aged 1-5 months 1, 2
Antibiotics eliminate B. pertussis from the nasopharynx but do not alter the subsequent clinical course of paroxysmal coughing, post-tussive vomiting, or apnea once the paroxysmal phase has begun 3
Monitor for infantile hypertrophic pyloric stenosis (IHPS): While azithromycin has a significantly lower risk than erythromycin, infants under 6 months receiving macrolides should be monitored for IHPS 1, 2

Position the infant upright or semi-upright during and after coughing episodes to reduce aspiration risk and facilitate mucus clearance 3
Offer small, frequent feedings rather than large volume feeds to minimize post-tussive vomiting 2
Maintain adequate hydration: Monitor for signs of dehydration from vomiting (decreased urine output, dry mucous membranes, sunken fontanelle) 2
Minimize stimuli that trigger coughing: Keep the environment calm, avoid sudden temperature changes, reduce exposure to irritants (smoke, strong odors) 2
Use a cool-mist humidifier to help keep airways moist, though evidence for benefit is limited 2

Apneic episodes (breathing pauses >10-15 seconds) are an indication for hospitalization 2
Severe post-tussive vomiting leading to dehydration or inability to maintain oral intake is an indication for hospitalization 1
Respiratory distress (grunting, nasal flaring, retractions, tachypnea) is an indication for hospitalization 3
Oxygen desaturation below 90-92% is an indication for hospitalization 2
Any concerning change in mental status or lethargy is an indication for hospitalization 2, 3
Infants under 6 months, especially under 4 months, have the highest risk of severe and fatal pertussis complications, so maintain a very low threshold for hospital admission 2

Do not use cough suppressants (dextromethorphan, codeine): These have no proven benefit in controlling pertussis paroxysms and may be harmful in infants 3
Do not use corticosteroids, long-acting β-agonists, antihistamines, or pertussis immunoglobulin: None of these therapies have demonstrated benefit in controlling coughing paroxysms 3
Do not give azithromycin with aluminum- or magnesium-containing antacids simultaneously, as they reduce absorption 1, 2

Paroxysmal coughing will persist for weeks to months despite appropriate antibiotic therapy, as the disease typically lasts 6-10 weeks total (the "100-day cough") 3
The infant becomes non-infectious after 5 days of azithromycin but symptoms will continue 3
Approximately 80-90% of untreated patients spontaneously clear B. pertussis within 3-4 weeks, but treatment is still indicated to prevent transmission 3

All household contacts should receive prophylaxis with the same antibiotic regimen (azithromycin dosing per age), especially critical given the presence of a vulnerable infant 2, 3
Symptomatic household members should be treated as if they have pertussis 2