My child has had a cough for three weeks and is now coughing up blood‑tinged (red) sputum; what does this indicate and do we need urgent medical evaluation?

Blood-Tinged Sputum in a Child with 3-Week Cough

Your child needs urgent medical evaluation today to rule out serious underlying conditions, particularly pertussis (whooping cough), pneumonia, or other potentially progressive respiratory diseases that can present with hemoptysis after prolonged cough. 1

Why This Requires Immediate Assessment

• Blood in sputum is never normal in children and warrants chest radiography to exclude pneumonia, foreign body aspiration, or other serious pulmonary pathology. 1

• At 3 weeks duration, this cough has crossed into the "prolonged acute cough" category (3-8 weeks), which significantly increases the likelihood of serious underlying disease compared to typical viral upper respiratory infections that resolve within 1-3 weeks. 1, 2

• Up to 30.8% of children with cough persisting beyond 4 weeks have serious chronic lung disease including chronic pneumonia, bronchiectasis, or aspiration lung disease when systematically evaluated. 1

Critical Diagnoses to Rule Out Immediately

Pertussis (Whooping Cough)

• Pertussis must be specifically assessed by asking about three classical features: paroxysmal cough (recurrent prolonged coughing episodes with inability to breathe during spells), post-tussive vomiting (vomiting induced by coughing), and inspiratory whooping (continuous inspiratory airway sound with whooping quality). 1

• Pertussis can cause violent coughing paroxysms that rupture small blood vessels, leading to blood-tinged sputum, and the infection is highly contagious with 70-100% household transmission rates. 1

• If pertussis is suspected clinically, start macrolide antibiotics immediately without waiting for laboratory confirmation and isolate the child for 5 days from treatment start to prevent transmission to other household members. 1, 3

• The cough from pertussis typically persists for 2-6 weeks after treatment but can last months despite appropriate antibiotics, as treatment eliminates the bacteria but doesn't modify the established cough reflex hypersensitivity. 3

Bacterial Pneumonia or Persistent Bacterial Bronchitis

• Chest radiograph is mandatory to exclude pneumonia, which can present with hemoptysis and prolonged cough. 1

• Persistent bacterial bronchitis occurs when an initial dry viral cough becomes a prolonged wet cough with purulent sputum that persists long after the febrile illness resolves, and this responds to a completed 2-week course of appropriate antibiotics. 4, 5

Other Serious Conditions

• Foreign body aspiration must be considered, particularly if there was any choking episode or sudden onset of cough, as this can cause hemoptysis and progressive lung damage if not removed. 1

• Bronchiectasis or aspiration lung disease should be investigated if the child has recurrent respiratory infections, failure to thrive, or other systemic symptoms. 1

What the Emergency Department or Pediatrician Will Do

Immediate Evaluation

• Detailed history focusing on: timing of blood appearance, amount of blood, presence of paroxysmal coughing, post-tussive vomiting, whooping sounds, fever pattern, and any choking episodes. 1

• Physical examination assessing respiratory rate, oxygen saturation, work of breathing, and auscultation for focal findings suggesting pneumonia or foreign body. 1

• Chest radiograph to identify infiltrates, foreign bodies, or structural abnormalities. 1

Laboratory Testing

• Nasopharyngeal swab for pertussis PCR if any features suggest whooping cough, as culture sensitivity is only 25-50% but PCR is 88-100% specific. 1

• Complete blood count may show lymphocytosis in pertussis, though this is frequently absent in children. 1

Common Pitfalls to Avoid

• Do not assume this is "just a lingering cold" when hemoptysis is present—blood-tinged sputum always requires investigation in children. 1

• Do not wait for "classic whooping" to diagnose pertussis, as many children (especially those partially vaccinated) present with atypical prolonged cough without the characteristic whoop. 1, 6

• Do not give cough suppressants before evaluation, as cough is a protective mechanism and suppression can be harmful or even fatal in children with underlying respiratory disease. 7

• Do not delay evaluation for "a few more days" to see if it improves—serious conditions like foreign body aspiration or progressive bronchiectasis cause irreversible lung damage when diagnosis is delayed. 1

Expected Timeline After Evaluation

• If pertussis is confirmed, expect cough to persist for median 29-61 days depending on vaccination status, despite appropriate antibiotic treatment. 2

• If bacterial pneumonia or bronchitis is diagnosed, cough should improve within 1-2 weeks of appropriate antibiotics. 1, 4

• If post-infectious cough is the final diagnosis (after excluding serious causes), expect resolution within 3-8 weeks total from initial illness onset. 2, 8