What is the management and treatment of pertussis (whooping cough)?

Management and Treatment of Pertussis

Azithromycin is the first-line antibiotic for treating pertussis across all age groups, with a 5-day regimen (10 mg/kg on day 1, then 5 mg/kg daily for days 2-5) that is equally effective as erythromycin but significantly better tolerated. 1

Antibiotic Treatment

First-Line Therapy: Azithromycin

• Azithromycin is preferred over erythromycin due to superior tolerability, shorter treatment duration (5 days vs 14 days), and markedly better compliance—90% of patients complete azithromycin versus only 55% completing erythromycin 2
• Dosing for infants <6 months: 10 mg/kg/day for 5 days 1
• Dosing for children ≥6 months and adolescents: 10 mg/kg (maximum 500 mg) on day 1, then 5 mg/kg (maximum 250 mg) daily for days 2-5 1
• Dosing for adults: 500 mg on day 1, then 250 mg daily for days 2-5 1
• Critical safety advantage: Azithromycin has significantly lower risk of infantile hypertrophic pyloric stenosis (IHPS) compared to erythromycin in infants <1 month 1
• Do not administer azithromycin with aluminum- or magnesium-containing antacids as they reduce absorption 1

Alternative Macrolides

• Clarithromycin: 7.5 mg/kg (maximum 500 mg) twice daily for 7 days for children; 500 mg twice daily for 7-10 days for adults 1
• Erythromycin (if azithromycin unavailable): 40-50 mg/kg/day in divided doses for children, 1-2 g/day for adults, for 14 days 1, 3
• Avoid erythromycin in infants <1 month due to IHPS risk 1

Non-Macrolide Alternative

• Trimethoprim-sulfamethoxazole (TMP-SMZ): For patients >2 months with macrolide contraindications or hypersensitivity 1

Timing of Treatment and Expected Outcomes

Early Treatment (Catarrhal Phase: First 1-2 Weeks)

• Antibiotics started during the catarrhal stage rapidly clear B. pertussis from the nasopharynx, decrease coughing paroxysms, and reduce complications 1
• This is the critical window for clinical benefit—treatment reduces symptom duration and severity by approximately 50% 4

Late Treatment (Paroxysmal Phase: >3 Weeks)

• Even when started during the paroxysmal stage, antibiotics remain essential to eradicate B. pertussis and prevent transmission, though they have limited effect on established cough 1
• 80-90% of untreated patients spontaneously clear the organism within 3-4 weeks from cough onset 1
• Start treatment immediately upon clinical suspicion without waiting for culture confirmation 1

Isolation and Infection Control

• Isolate patients for 5 days after starting antibiotics to prevent transmission 1
• If antibiotics cannot be administered, isolate for 21 days after cough onset 5
• Healthcare workers with pertussis must be restricted from work during the first 5 days of antibiotic therapy 5
• Wear a surgical mask when within 3 feet of a patient with confirmed or suspected pertussis 5

Postexposure Prophylaxis

Who Requires Prophylaxis

• All close contacts require macrolide prophylaxis within 21 days of exposure, regardless of age and vaccination status 1
• Prioritize prophylaxis for high-risk contacts: infants <12 months, pregnant women in third trimester, and healthcare workers with known exposure 1
• Secondary attack rates exceed 80% among susceptible household contacts, making prophylaxis critical 4

Prophylaxis Regimens

• Use the same antibiotic agents and dosing regimens as for treatment 1
• Erythromycin: 40-50 mg/kg/day for children, 500 mg four times daily for adults, for 14 days 5
• Azithromycin or clarithromycin: Alternative options with better tolerability 5

Therapies to Avoid

Do not use β-agonists, antihistamines, corticosteroids, or pertussis immunoglobulin—these have no proven benefit in controlling coughing paroxysms or improving outcomes 1

Vaccination Considerations

• Neither vaccination nor natural disease confers lifelong immunity—breakthrough infections occur due to waning immunity 5-10 years post-vaccination 4
• Continue routine DTaP vaccination schedule for household contacts who are not up-to-date 4
• No recommendation exists for administering additional pertussis vaccine doses to children with documented pertussis disease 5

Monitoring for Complications

Common Complications

• Weight loss and sleep disturbance occur frequently and should be monitored 6
• Post-tussive vomiting is characteristic, especially in vaccinated children with breakthrough infections 4

Pressure-Related Effects from Severe Coughing

• Pneumothorax, epistaxis, subconjunctival hemorrhage, and rib fractures can occur 4

Infectious Complications

• Primary or secondary bacterial pneumonia and otitis media may complicate the course 4

Serious Neurological Complications

• Seizures and hypoxic encephalopathy are infrequent but require immediate evaluation, particularly in infants 6

Common Pitfalls to Avoid

• Do not dismiss pertussis based solely on vaccination status—breakthrough infections occur and vaccinated children often present with atypical symptoms without the characteristic "whoop" 4
• Do not delay testing or treatment while waiting for classic symptoms to develop—early intervention reduces transmission and may shorten disease course 4
• Do not assume antibiotics are ineffective in late-stage disease—while they won't stop established cough, they remain critical for preventing transmission 1
• Do not forget to treat all household contacts prophylactically, as pertussis remains highly contagious even in vaccinated individuals with breakthrough infections 4