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Pertussis (Whooping Cough) Cough

What is Pertussis (whooping cough) cough?

Pertussis, commonly known as whooping cough, is an acute respiratory infection caused by the bacterium _Bordetella pertussis_. The hallmark of the disease is a severe, paroxysmal cough that often ends with a high‑pitched “whoop” sound as the patient inhales. The cough can be so forceful that it leads to vomiting, rib fractures, or even fainting. While it is most notorious in infants and young children, adolescents and adults can also be infected and may experience a milder but still disruptive cough.

The illness typically progresses through three phases:

• Catarrhal phase (1‑2 weeks): Mild cold‑like symptoms—runny nose, low‑grade fever, and occasional cough.
• Paroxysmal phase (1‑6 weeks): Sudden, violent coughing fits that may end with the classic “whoop.” This is the period most people recognize as pertussis.
• Convalescent phase (weeks to months): Cough gradually lessens but can linger for months, especially after exertion or exposure to cold air.

Because the cough can mimic many other respiratory conditions, understanding the underlying cause is essential for proper treatment.

Common Causes

While pertussis itself is caused by a specific bacterium, a cough that resembles the “whooping” pattern can be triggered by several other conditions. Recognizing these alternatives helps clinicians rule out pertussis and guides appropriate therapy.

• Bordetella pertussis infection (true pertussis) – The classic bacterial cause.
• Viral respiratory infections – e.g., adenovirus, respiratory syncytial virus (RSV), and influenza can produce harsh coughing fits.
• Asthma – Airway hyper‑responsiveness leads to coughing that may be worsened at night.
• Allergic rhinitis or post‑nasal drip – Irritates the throat, provoking a chronic cough.
• Chronic bronchitis (COPD exacerbation) – Particularly in smokers, coughing may be deep and frequent.
• Airway irritants – Smoke, dust, chemicals, or occupational exposures.
• Gastroesophageal reflux disease (GERD) – Acid reflux can trigger a cough that mimics a pertussis spell.
• Foreign body aspiration – Particularly in children, an object lodged in the airway can produce sudden, forceful coughing.
• Bronchiectasis – Dilated airways produce a persistent, productive cough.
• Neurological disorders – Conditions such as cerebral palsy or spinal cord injury can impair airway clearance, leading to coughing episodes that may sound like pertussis.

Associated Symptoms

The cough of pertussis rarely occurs in isolation. Typical accompanying signs include:

• Whooping sound on inhalation after a coughing spell (more common in children).
• Vomit after coughing – intense bouts often expel stomach contents.
• Facial flushing or cyanosis – due to reduced oxygen during a paroxysm.
• Low‑grade fever (often <38°C/100.4°F) during the catarrhal phase.
• Runny nose, mild sore throat early in the illness.
• Fatigue & sleep disturbance – coughing frequently awakens patients.
• Chest pain or rib tenderness from repeated muscular strain.
• Apnea (in infants) – brief pauses in breathing that can be life‑threatening.

When to See a Doctor

Because pertussis is highly contagious and can be severe—especially in infants—prompt medical attention is crucial when any of the following occur:

• New cough lasting more than 2 weeks with paroxysms or a whooping sound.
• Cough accompanied by vomiting, weight loss, or night sweats.
• Signs of respiratory distress: rapid breathing, wheezing, or bluish lips/face.
• Infants under 12 months with cough, apnea, or a fever >38°C (100.4°F).
• Pregnant women or individuals with chronic lung disease who develop a severe cough.
• Any patient who has been in close contact with a confirmed case of pertussis.

Early diagnosis allows for antibiotics that reduce contagion and can shorten the illness.

Diagnosis

Physicians use a combination of clinical assessment and laboratory testing:

1. Clinical History & Physical Exam

• Duration, pattern (paroxysmal), and triggers of cough.
• Vaccination history (DTaP/Tdap).
• Search for whoop, post‑tussive vomiting, or apnea.

2. Laboratory Tests

• PCR (polymerase chain reaction) of nasopharyngeal swab: Most sensitive within the first 3 weeks.
• Culture: Gold standard but slower (takes 5‑7 days) and less sensitive after the catarrhal phase.
• Serology: Detects antibodies (IgG) against pertussis toxin; useful later in the illness.

3. Additional Evaluations (if alternative cause suspected)

• Chest X‑ray – to rule out pneumonia or bronchiectasis.
• Spirometry – if asthma or COPD is a concern.
• pH probe or esophageal manometry – for GERD‑related cough.

Treatment Options

Treatment is aimed at eliminating the bacteria, relieving symptoms, and preventing complications.

Medical Therapies

• Antibiotics – First‑line agents include:
  • Azithromycin 10 mg/kg on day 1, then 5 mg/kg daily for 4 days (or 500 mg adult dose).
  • Erythromycin 40‑50 mg/kg/day divided q6h for 14 days (adult 500 mg q6h).
  • Clarithromycin 7.5 mg/kg twice daily for 7 days (adult 500 mg q12h).
  Early administration (within 3 weeks of cough onset) shortens infectivity and may reduce symptom severity. CDC, 2023
• Supportive care – Intravenous fluids for dehydration, antipyretics (acetaminophen or ibuprofen) for fever, and bronchodilators if wheezing is present.
• Hospitalization – Recommended for infants <2 months, severe apnea, dehydration, or when oxygen saturation falls <90 %.

Home & Self‑Care Measures

• Humidity: Use a cool‑mist humidifier to soothe irritated airways.
• Fluid intake: Keep the patient well‑hydrated to thin secretions.
• Positioning: Elevate the head of the bed; sit upright during coughing spells to reduce aspiration risk.
• Small, frequent meals: Helps prevent vomiting after coughing.
• Avoid irritants: Smoke, strong fragrances, and dusty environments can worsen cough.
• Honey (for children >1 year) or warm tea: May provide temporary soothing, but never give honey to infants <1 year.

Prevention Tips

Vaccination is the most effective strategy against pertussis.

• DTaP series for infants (5 doses at 2, 4, 6, 15‑18 months, and 4‑6 years).
• Tdap booster at age 11‑12 and then every 10 years for adults, especially pregnant women (ideally between 27‑36 weeks gestation).
• Cocooning: Vaccinate household contacts and caregivers of newborns.
• Practice good respiratory hygiene – covering coughs, hand washing, and avoiding close contact with sick individuals.
• Stay home while infectious (usually 5 days after starting antibiotics).

Emergency Warning Signs

Key Take‑aways

Pertussis remains a public‑health concern because of its contagious nature and potential severity in young infants. Recognizing the characteristic paroxysmal cough, seeking timely medical evaluation, and completing the recommended antibiotic course are essential steps. Vaccination, both in childhood and as adult boosters, remains the cornerstone of prevention.

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References:

• Mayo Clinic. “Whooping cough (pertussis).” Updated 2024. https://www.mayoclinic.org
• Centers for Disease Control and Prevention. “Pertussis (Whooping Cough) – Clinical Overview.” 2023. https://www.cdc.gov
• National Institutes of Health. “Pertussis (Whooping Cough).” 2024. https://www.niaid.nih.gov
• World Health Organization. “Pertussis vaccines: WHO position paper.” 2022. https://www.who.int
• Cleveland Clinic. “Whooping cough – Symptoms, causes, and treatment.” 2024. https://my.clevelandclinic.org

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