What should I do if a 4-year-old child presents with symptoms suggestive of pertussis (whooping cough), including a productive cough and increased respiratory rate?

Immediate Management of Suspected Pertussis in a 4-Year-Old

This child requires immediate pertussis testing (PCR preferred) and prompt initiation of macrolide antibiotic therapy, specifically azithromycin, to prevent transmission to others, even though antibiotics will not alter the clinical course at this stage. 1, 2, 3

Initial Assessment and Diagnostic Approach

Evaluate for the three classical characteristics of pertussis:

• Paroxysmal cough (present in your case with "whooping" sound)
• Post-tussive vomiting (assess if present)
• Inspiratory whooping (described as present) 1, 4

Obtain confirmatory testing immediately:

• PCR testing for Bordetella pertussis is the preferred diagnostic test, having replaced culture as the gold standard 1, 3
• Culture can also be used but takes longer 2
• Serology is not routinely recommended or standardized 2

Obtain a chest radiograph to rule out complications such as pneumonia and other causes of respiratory distress 1, 4

Antibiotic Treatment Protocol

Start azithromycin immediately as the first-line antibiotic for pertussis 2, 3:

• The primary goal is to eradicate nasal bacterial carriage and reduce transmission rates, not to improve symptoms 2, 3
• Antibiotics are most effective when started early in the course of illness, though they may not alter the clinical course if started late 1, 2
• Trimethoprim/sulfamethoxazole is an alternative only in cases of macrolide allergy or intolerance 2

Critical timing consideration: While antibiotics won't improve this child's symptoms at this stage, they are essential to prevent spread to household contacts and other children 2, 3

Household Contact Management

Provide antibiotic prophylaxis to all household contacts:

• All household contacts should receive azithromycin prophylaxis regardless of vaccination status 3
• This is particularly critical if there are infants in the home, pregnant women in third trimester, or immunocompromised individuals 3
• Note that "cocooning" (vaccinating close contacts) is no longer recommended because immunized patients can still contract and transmit pertussis 3

Monitoring for Complications

Assess for age-specific complications:

• While infants face the highest risk of severe complications (apnea, pneumonia, seizures, death), 4-year-olds can still develop pneumonia, subconjunctival hemorrhage, and rarely pulmonary hypertension or encephalopathy 5, 6
• Monitor respiratory rate and work of breathing closely 1
• Watch for signs of respiratory distress requiring hospitalization 6

What NOT to Do

Avoid these common pitfalls:

• Do not use dexamethasone or oral steroids—they provide no significant benefit for symptomatic relief of pertussis cough 4
• Do not empirically treat for asthma unless other features consistent with asthma are present 1, 7
• Do not delay antibiotic treatment while awaiting test results if clinical suspicion is high 2, 8
• Do not use over-the-counter cough medications—they have not been shown to make cough less severe or resolve sooner 7

Follow-Up and Parental Counseling

Provide specific guidance to parents:

• Explain that the cough will persist for weeks despite antibiotics (the "100-day cough") 8, 3
• The disease evolves through three stages: catarrhal (nonspecific symptoms), paroxysmal (severe coughing with whooping), and convalescent (persistent cough) 2, 3
• Address parental concerns about serious illness, sleep disturbance, and potential for permanent chest damage 4
• Instruct parents to return if the child develops increased work of breathing, cyanosis, apnea, or inability to feed 6

If cough persists beyond 4 weeks, reclassify as chronic cough and follow pediatric-specific cough management protocols, reassessing for other etiologies 1, 4

Vaccination Status Review

Verify and update immunization status:

• Review the child's DTaP vaccination history 5, 2
• Note that vaccine immunity wanes over time, and even fully immunized children can develop pertussis, though typically with milder disease 5, 3
• Ensure household contacts, especially pregnant women, have received Tdap (pregnant women should receive Tdap between 27-36 weeks' gestation with each pregnancy) 3