Whooping Cough (Pertussis) in Children: Symptoms, Treatment and Prevention
It starts like an ordinary cold. Runny nose, mild cough, low-grade fever. By the end of the second week, the cough has become something unmistakable: violent, uncontrollable bursts that leave a child gasping for air and producing the characteristic high-pitched whooping sound that gives whooping cough pertussis its common name.
Whooping cough pertussis is one of the most preventable yet persistently common vaccine-preventable diseases in the United States. Despite widespread vaccination, outbreaks occur every few years, affecting thousands of children and adults. In infants under six months, whooping cough pertussis can be life-threatening. In older children and teenagers, it produces weeks of debilitating coughing that disrupts sleep, school, and daily life.
Recognizing whooping cough pertussis early, understanding how the illness progresses, knowing who is most at risk, and understanding what treatment and prevention look like are the foundations of protecting your child and your household. At All Kidz Urgent Care in Torrance, California, our board-certified pediatricians evaluate and treat whooping cough pertussis throughout the year. This guide gives South Bay parents the clear, complete information they need to act quickly when it matters most.
What Is Whooping Cough Pertussis?
Whooping cough pertussis is a highly contagious bacterial respiratory infection caused by Bordetella pertussis, a bacterium that attaches to the cilia lining the upper respiratory tract and releases toxins that damage the airway and trigger the body’s cough response. Unlike viral respiratory infections that resolve in one to two weeks, whooping cough pertussis follows a prolonged course that can last six to ten weeks from first symptom to full recovery, earning it the nickname the hundred-day cough in many countries. Whooping cough pertussis spreads through respiratory droplets produced when an infected person coughs, sneezes, or breathes in close proximity to others. It is extraordinarily contagious. In an unprotected household, a single infected person will transmit whooping cough pertussis to up to 90 percent of susceptible close contacts. The incubation period is typically seven to ten days but can extend to twenty-one days.
The Centers for Disease Control and Prevention reports tens of thousands of whooping cough pertussis cases annually in the United States, with periodic epidemic cycles every three to five years. The disease affects people of all ages, but the most severe cases and the highest mortality occur in infants under twelve months, particularly those under six months who have not yet completed their primary vaccination series.
The Three Stages of Whooping Cough Pertussis
Understanding the three clinical stages of whooping cough pertussis is one of the most important pieces of knowledge a parent can have, because the window for most effective antibiotic treatment occurs in the earliest stage when the illness looks almost indistinguishable from a common cold.
Stage One: The Catarrhal Stage (Weeks One to Two)
The catarrhal stage of whooping cough pertussis is the most contagious period of the entire illness. It begins with symptoms that are nearly identical to an ordinary upper respiratory infection: runny nose, mild congestion, sneezing, low-grade fever, and a mild cough that gradually worsens over the course of one to two weeks.
This stage is the critical diagnostic window. Antibiotic treatment given during the catarrhal stage can significantly reduce the severity and duration of the illness and, most importantly, reduce the period during which the infected child is contagious to others. After the catarrhal stage has passed, antibiotics have little effect on the course of the coughing illness itself, though they remain important for reducing transmission.
The challenge is that nothing about the catarrhal stage announces itself as whooping cough pertussis. Parents and even clinicians often attribute these early symptoms to a routine cold. The alert that should raise suspicion during this stage is exposure: if your child has been around someone confirmed or suspected to have whooping cough pertussis, or if there is a known outbreak in your community or school, the catarrhal stage presentation warrants prompt evaluation and testing.
Stage Two: The Paroxysmal Stage (Weeks Two to Six)
The paroxysmal stage is when whooping cough pertussis becomes unmistakable. The mild cough of the first stage transforms into sudden, violent bursts of rapid coughing that can include ten to twenty coughs in a single breath. These coughing fits, or paroxysms, occur because the damaged airway cannot clear the thick mucus effectively, forcing the child into repeated coughing attempts to dislodge it.
At the end of each paroxysm, the child gasps for air through a partially obstructed upper airway, producing the characteristic high-pitched whoop. This sound is most prominent in children and less reliable in infants, who may not whoop at all but instead may gag, vomit, or turn blue from the oxygen deprivation caused by prolonged coughing fits.
Paroxysms can be triggered by eating, drinking, crying, or physical activity. They occur both day and night, with nighttime episodes often being the most severe. Post-tussive vomiting, meaning vomiting immediately after a coughing fit, is very common and is one of the features that distinguishes whooping cough pertussis from other respiratory illnesses. Between episodes, children often appear relatively well, which can be misleading about the severity of the overall illness.
Complications are most likely to occur during the paroxysmal stage. In infants, apnea during or after coughing fits is a serious and potentially life-threatening complication. Pneumonia, the most common cause of whooping cough pertussis-related death in infants, typically develops during this stage. Rib fractures from the force of prolonged severe coughing can occur in older children and adults.
Stage Three: The Convalescent Stage (Weeks Six to Ten or Beyond)
The convalescent stage is characterized by gradually decreasing frequency and severity of coughing paroxysms. The cough does not disappear suddenly. It fades slowly over weeks. Many children experience a resurgence of coughing with any subsequent respiratory infection for months after recovering from whooping cough pertussis, because the airway damage takes considerable time to fully heal.
During the convalescent stage, the child is generally no longer contagious, particularly if they completed a course of antibiotics during the earlier stages. The focus of management shifts entirely to supportive care, maintaining nutrition and hydration, and managing the residual cough.
Whooping Cough Pertussis in Different Age Groups
The clinical presentation and the stakes of whooping cough pertussis differ significantly depending on your child’s age, and the younger the child, the more seriously any suspected case must be taken.
Infants Under Six Months
This is the highest-risk group for severe and fatal whooping cough pertussis. Infants in this age group have not completed their primary DTaP vaccination series and have minimal immune protection against Bordetella pertussis. The characteristic whoop is often absent in very young infants. Instead, the presentation may include brief pauses in breathing or apnea, cyanosis or bluish skin color during or after coughing, gagging or choking, poor feeding, and extreme fatigue following coughing episodes.
Infants under six months with suspected whooping cough pertussis should be evaluated urgently. Many will require hospitalization for monitoring, oxygen support, and intravenous feeding if oral intake is severely compromised. The mortality rate from whooping cough pertussis is highest in this age group and is most often caused by pneumonia or hypoxic brain injury from repeated apnea episodes. Visit our newborn care services page for information on how All Kidz Urgent Care approaches evaluation in young infants.
Infants Six to Twelve Months
Infants in this age group may have received one to three doses of the DTaP vaccine depending on their age and vaccination schedule. Partial vaccination reduces the risk of severe disease but does not eliminate it. The classic whoop may be present but is less reliable than in older children. Post-tussive vomiting and apnea are still significant concerns. Prompt evaluation is warranted for any infant in this age group with a cough that is worsening rather than improving after the first week of illness.
Toddlers and Preschool Children (1 to 5 Years)
Children in this age group who are up to date on their DTaP series have meaningful protection but can still contract whooping cough pertussis, particularly as vaccine-induced immunity wanes. The classic paroxysmal cough with the terminal whoop is typically present in this age group and is the most useful diagnostic clue. Post-tussive vomiting is common. Complications including pneumonia occur less frequently than in younger infants but still warrant attention. Any child in this age group with prolonged coughing lasting more than one to two weeks should be evaluated for whooping cough pertussis.
School-Age Children and Teenagers (6 to 21 Years)
Older children and teenagers represent a significant reservoir for whooping cough pertussis transmission because their disease is often milder and atypical enough to be misdiagnosed or dismissed as a persistent cough from another cause. The characteristic whoop may be absent. The most prominent symptom is a prolonged, distressing cough that disrupts sleep and daily activities for weeks. Teenagers who are not up to date on their Tdap booster, recommended at age eleven to twelve, are at elevated risk. All Kidz Urgent Care sees young adults through age 21 and can evaluate, test, and treat whooping cough pertussis in this age group.
How Whooping Cough Pertussis Is Diagnosed
Diagnosis of whooping cough pertussis is based on the combination of clinical presentation and laboratory testing. The gold standard for diagnosis is nasopharyngeal culture, in which a swab taken from the back of the nasal passage is cultured for Bordetella pertussis. Culture is most sensitive during the catarrhal stage and early paroxysmal stage when bacterial load is highest.
Polymerase chain reaction testing, commonly called PCR, is faster than culture and highly sensitive, making it the most commonly used diagnostic test in clinical practice. A nasopharyngeal swab is collected and tested for the genetic material of Bordetella pertussis. PCR can remain positive for several weeks into the paroxysmal stage even after antibiotic treatment has begun. Blood testing showing elevated white blood cell count with lymphocytosis can support the diagnosis, particularly in infants. Serology testing for antibodies is available and useful later in the illness when culture and PCR sensitivity decline, but it is less commonly used in routine clinical practice.
The clinical diagnosis, based on the characteristic cough pattern, duration, post-tussive vomiting, and whoop, is often sufficient to initiate treatment while awaiting laboratory confirmation, particularly when there is known community exposure or outbreak activity.
Treatment of Whooping Cough Pertussis
Treatment of whooping cough pertussis serves two distinct purposes: reducing the severity and duration of illness when given early, and reducing contagiousness to protect household contacts and the broader community. Antibiotics are the primary treatment for whooping cough pertussis. Azithromycin is the first-line antibiotic for most children and is given as a five-day course. Clarithromycin is an alternative for older children. Trimethoprim-sulfamethoxazole is used for children who cannot take macrolide antibiotics. Erythromycin, an older macrolide, is effective but associated with a risk of a serious condition called hypertrophic pyloric stenosis in infants under one month of age and is generally avoided in this age group.
When antibiotics are started during the catarrhal stage, they can meaningfully reduce the severity of subsequent coughing and shorten the contagious period. When started during the paroxysmal stage, they have minimal effect on the clinical course of the coughing illness but remain important for reducing the child’s contagiousness to others, particularly vulnerable household contacts such as unvaccinated infants.
Household contacts of a confirmed case of whooping cough pertussis should receive prophylactic antibiotic treatment regardless of their vaccination status, particularly if any unvaccinated or incompletely vaccinated infants are in the household. This is called post-exposure prophylaxis and follows the same antibiotic regimen as treatment. For guidance on managing respiratory illness in infants specifically, visit our RSV in children page and our upper respiratory infections page for context on how whooping cough pertussis differs from other common respiratory illnesses.
Supportive care during the paroxysmal stage focuses on maintaining hydration and nutrition, which can be significantly compromised by frequent post-tussive vomiting. Smaller, more frequent feeds reduce the volume load on the stomach and the likelihood of vomiting following feeds. Keeping the child calm reduces the frequency of coughing triggers. Cool, humidified air can ease breathing. Avoid cough suppressants, which are not effective for the paroxysmal cough of whooping cough pertussis and can mask important clinical changes. Infants with severe disease require hospitalization for continuous monitoring of oxygen saturation and breathing, supplemental oxygen, intravenous fluids, and in the most severe cases, intensive respiratory support.
Prevention: Vaccination Against Whooping Cough Pertussis
Vaccination is the single most effective tool for preventing whooping cough pertussis and its most serious complications. The DTaP vaccine, which protects against diphtheria, tetanus, and pertussis, is given as a primary series at two months, four months, six months, fifteen to eighteen months, and four to six years of age. The Tdap booster, a lower-dose formulation appropriate for older children and adults, is recommended at eleven to twelve years and for adults who have not previously received it.
Vaccine-induced immunity against whooping cough pertussis wanes over time. This is a critical and often misunderstood aspect of pertussis epidemiology. Vaccinated children and adults can contract whooping cough pertussis, typically with milder disease than unvaccinated individuals, but they can still transmit it to others, including vulnerable unvaccinated infants. This is why booster vaccination is important and why pertussis outbreaks continue to occur in communities with high overall vaccination rates.
The cocooning strategy is the approach recommended by the American Academy of Pediatrics for protecting newborns who are too young to be vaccinated. It involves ensuring that all household members and close caregivers, including parents, grandparents, and childcare providers, are up to date on their Tdap vaccination before or immediately after the baby arrives. By surrounding the infant with protected individuals, the strategy reduces the likelihood of the infant being exposed to whooping cough pertussis before they can be vaccinated.
Maternal Tdap vaccination during pregnancy, recommended between 27 and 36 weeks of gestation by the Centers for Disease Control and Prevention, provides passive antibody protection to the newborn through placental transfer. This is currently the most direct way to provide protection to infants from birth until they can begin their own vaccination series. For families expecting a new baby and wanting guidance on protecting their newborn from whooping cough pertussis and other respiratory illnesses, visit our expectant parents consultation page.
Staying current on the recommended vaccination schedule for your child is the most important action you can take. If you are unsure whether your child is up to date on their DTaP or Tdap vaccination, our team at All Kidz Urgent Care can review your child’s vaccination history and advise on any needed doses.
Myth Busting: Common Misconceptions About Whooping Cough Pertussis
- Myth: Only unvaccinated children get whooping cough pertussis. This is false. Vaccinated children and adults can and do contract whooping cough pertussis as vaccine-induced immunity wanes over time. Vaccination significantly reduces the risk of severe disease and death but does not provide lifelong complete protection. Outbreaks occur in highly vaccinated populations regularly.
- Myth: The whoop is always present. The characteristic whooping sound is absent in a significant proportion of cases, particularly in very young infants, adults, and teenagers. The absence of a whoop does not rule out whooping cough pertussis. Prolonged cough lasting more than two weeks with post-tussive vomiting should prompt testing regardless of whether the whoop is present.
- Myth: Whooping cough pertussis is a disease of the past. Whooping cough pertussis is a current and ongoing public health concern. The CDC documents tens of thousands of cases annually in the United States, with epidemic cycles occurring regularly. It remains one of the most common vaccine-preventable diseases in developed countries.
- Myth: Antibiotics will cure the cough quickly. Antibiotics reduce contagiousness and can reduce severity when given early, but they do not immediately resolve the paroxysmal cough once it has established. The cough follows its own timeline regardless of antibiotic treatment once the paroxysmal stage is underway. Parents should be counseled to expect weeks of coughing even after a full course of antibiotics has been completed.
When to Visit All Kidz Urgent Care
Bring your child to All Kidz Urgent Care if they have a cough that is worsening rather than improving after the first week of illness, coughing fits that end in a whoop, gagging, or vomiting, known exposure to a confirmed case of whooping cough pertussis, a prolonged cough lasting more than two weeks without clear explanation, or any infant under twelve months with a cough that is becoming more severe or frequent.
Seek emergency care immediately or call 911 if your infant turns blue during a coughing episode, stops breathing or has apnea, loses consciousness, or appears severely distressed and is unable to feed. For walk-in evaluation, testing, and treatment of whooping cough pertussis, visit All Kidz Urgent Care at 2927 Rolling Hills Road, Unit 20, Torrance, CA 90505. Our board-certified pediatricians can evaluate the full clinical picture, perform nasopharyngeal testing, initiate antibiotic treatment, and advise on prophylaxis for household contacts. Visit our urgent care services page for walk-in hours and directions, or call us at (310) 292-0054. For information on how whooping cough pertussis compares to other respiratory infections your child may be experiencing, visit our viral vs bacterial respiratory infections page.
Frequently Asked Questions (FAQs) about Whooping Cough Pertussis
- How long is whooping cough pertussis contagious?
Whooping cough pertussis is most contagious during the catarrhal stage and for the first two weeks of the cough. After five days of appropriate antibiotic treatment, the contagious period is considered to have ended. Without antibiotic treatment, a person with whooping cough pertussis may remain contagious for up to three weeks after the onset of coughing. - My child was vaccinated but has a prolonged cough. Can they still have whooping cough pertussis?
Yes. Vaccine immunity wanes over time, and vaccinated children can contract whooping cough pertussis, typically with milder or atypical symptoms. A prolonged cough lasting more than two weeks in a vaccinated child still warrants evaluation and testing, particularly during periods of community outbreak activity. - Should all household members take antibiotics if one family member has whooping cough pertussis?
Yes. Post-exposure prophylaxis with antibiotics is recommended for all household contacts of a confirmed pertussis case regardless of vaccination status, particularly when there are unvaccinated or incompletely vaccinated infants in the household. Contact your pediatrician or visit All Kidz Urgent Care for prophylaxis guidance as soon as a household case is confirmed. - Can whooping cough pertussis cause permanent lung damage?
In the vast majority of cases, particularly in children and adults who receive appropriate treatment and supportive care, whooping cough pertussis does not cause permanent lung damage. The airway inflammation and hyperreactivity typically resolve fully during the convalescent stage, though this can take several months. Severe complications including pneumonia in infants can in rare cases result in longer-term respiratory consequences. - Is there a specific time of year when whooping cough pertussis is most common?
Whooping cough pertussis occurs year-round, unlike influenza or RSV which have more defined seasonal peaks. Epidemic cycles occur every three to five years regardless of season. Cases often cluster in school settings and spread to households from there, making the back-to-school period a common time for increased case detection.
Get Prompt Pediatric Care for Whooping Cough at All Kidz Urgent Care
Whooping cough can become serious, particularly for infants and young children, making timely pediatric evaluation important when symptoms persist or worsen. All Kidz Urgent Care provides pediatric-focused assessment for children experiencing prolonged coughing, coughing fits, vomiting after coughing, or other symptoms that may indicate pertussis.
Our board-certified pediatricians can evaluate your child’s symptoms, determine whether testing is appropriate, and recommend treatment based on the clinical findings. Same-day walk-in care also helps families seek attention without unnecessary delays when respiratory symptoms become concerning. If your child has been exposed to pertussis or develops a persistent or worsening cough, contact us or visit All Kidz Urgent Care in Torrance for professional evaluation, testing, treatment, and guidance for your family.
Location
2927 Rolling Hills Road Torrance,
California – 90505
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contactus@allkidzurgentcare.com
Recognizing whooping cough early can help families seek appropriate care and reduce the risk of spreading infection to others. All Kidz Urgent Care supports Torrance and South Bay families with pediatric-focused evaluation, testing, and treatment to help children receive timely care throughout their recovery.
