Croup vs. Whooping Cough: Key Differences in a Child's Cough
Key points
- Sound: A harsh, deep, "barking" cough, often compared to a seal or dog.
- Other Sounds: A high-pitched, squeaky noise called stridor may be heard when the child breathes in. Their voice may also be hoarse.
- Timing: The cough and breathing difficulties are notoriously worse at night and can be aggravated by crying or agitation.
When your child develops a cough, it can be a source of significant worry. Two common but very different respiratory illnesses, croup and whooping cough, can be particularly alarming for parents. While both involve severe coughing, they are caused by different pathogens, present with unique symptoms, and require distinct treatments. Understanding these differences is crucial for getting your child the right care quickly.
At-a-Glance: Croup vs. Whooping Cough Comparison
For a quick overview, this table highlights the primary distinctions between these two conditions.
| Feature | Croup | Whooping Cough (Pertussis) |
|---|---|---|
| Cause | Viral Infection | Bacterial Infection |
| Primary Pathogen | Parainfluenza viruses, RSV, influenza | Bordetella pertussis bacteria |
| Key Symptom | A loud, "barking" cough (like a seal), stridor (noisy breathing on inhale) | Intense, rapid coughing fits followed by a high-pitched "whoop" sound |
| Affected Age Group | Most common in children 6 months to 5 years | Can affect any age; most severe in infants under 1 year |
| Progression | Starts like a cold, barking cough develops quickly, often worse at night | Starts like a cold for 1-2 weeks, then severe coughing fits begin and last for weeks |
| Treatment | Home care (humidity, cool air), oral steroids for inflammation | Antibiotics are essential; supportive care, potential hospitalization for infants |
| Prevention | No specific vaccine (good hygiene helps) | DTaP and Tdap vaccines are highly effective |
| Severity | Usually mild and self-limiting | Can be very severe, with serious complications like pneumonia, seizures, and death |
The Sound of the Cough: The Most Telling Difference
Listening closely to your child's cough can provide the most immediate clue to what might be wrong.
Croup's "Barking" Cough
Croup is caused by a viral infection that leads to inflammation and swelling of the voice box (larynx) and windpipe (trachea). This narrowing of the upper airway forces air through a smaller passage, creating a distinctive sound.
- Sound: A harsh, deep, "barking" cough, often compared to a seal or dog.
- Other Sounds: A high-pitched, squeaky noise called stridor may be heard when the child breathes in. Their voice may also be hoarse.
- Timing: The cough and breathing difficulties are notoriously worse at night and can be aggravated by crying or agitation.
Whooping Cough's "Whoop"
Whooping cough, or pertussis, is a bacterial infection that attacks the lining of the breathing tubes. It produces a thick mucus that triggers violent, uncontrollable coughing fits.
- Sound: The illness is named for the sound made after a coughing spell. The child coughs repeatedly and rapidly (a paroxysm) until the air is expelled from their lungs, then gasps for breath with a high-pitched "whoop."
- Associated Symptoms: These coughing fits can be so severe they lead to vomiting, extreme fatigue, and a brief loss of consciousness.
- Important Note: Not everyone "whoops." Infants, in particular, may not have the strength to produce the sound and may instead gasp, gag, or even temporarily stop breathing (apnea).
!A microscopic image showing Bordetella pertussis bacteria, the cause of whooping cough. Image: Bordetella pertussis bacteria, which causes whooping cough. Source: CDC via Wikimedia Commons
Symptom Progression: From a Common Cold to a Distinct Illness
One of the most confusing aspects for parents is that both illnesses often start with similar, mild symptoms.
The Overlapping First Stage
For the first few days (in croup) or up to two weeks (in whooping cough), a child may seem to have a simple cold, with symptoms like:
- Runny or stuffy nose
- Sneezing
- A mild cough
- A low-grade fever
How Croup Develops
After 1-3 days of cold-like symptoms, croup's characteristic signs appear quite suddenly, usually in the middle of the night. The illness typically peaks on day three or four and resolves within a week.
How Whooping Cough Progresses
Whooping cough's progression is much slower and more insidious. After the initial 1-2 week "cold" stage, the cough gradually worsens into the severe, paroxysmal fits that define the illness. This coughing stage can last for up to 10 weeks, earning it the nickname "the 100-day cough."
Atypical Presentations: Not Everyone Follows the Textbook
While the classic descriptions are helpful, it's vital to know that symptoms can vary significantly, especially based on age and vaccination status.
- Infants: Very young infants with whooping cough often do not "whoop." Instead, their most dangerous symptom may be apnea (pauses in breathing) and cyanosis (turning blue or purple). For this reason, any severe cough in an infant requires immediate medical evaluation. Croup in infants may also present with less of a distinct "bark."
- Adults and Teens: Whooping cough in adolescents and adults, especially those who have been vaccinated, is often milder. It typically presents as a persistent, hacking cough that lasts for weeks, but without the classic "whoop."
- Vaccinated Individuals: A person vaccinated against pertussis can still get sick, but the illness is usually much less severe. This "vaccine-modified" pertussis may just seem like a prolonged case of bronchitis, but the individual is still contagious.
Diagnosis and Treatment: Getting the Right Care
Because the causes are different, the methods for diagnosis and treatment are also distinct.
How Doctors Diagnose Each Condition
- Croup: Diagnosis is almost always clinical, meaning the doctor can identify it by listening to the barking cough and stridor and assessing the child's breathing. In some cases, a neck X-ray may show a "steeple sign," which indicates narrowing of the airway.
- Whooping Cough: A definitive diagnosis requires a laboratory test. A doctor will take a mucus sample from the back of the nose or throat using a swab, which is then tested via PCR or culture to detect the Bordetella pertussis bacteria.
Treatment Approaches
- Croup: Since it's viral, antibiotics are ineffective. Treatment focuses on managing symptoms.
- Mild Cases: Can often be managed at home using moisture from a steamy bathroom or exposure to cool night air, which can help reduce airway swelling.
- Moderate to Severe Cases: A doctor may prescribe a single dose of an oral steroid (like dexamethasone) to decrease inflammation. In severe cases, a nebulized epinephrine treatment may be given in the emergency room.
- Whooping Cough: As a bacterial infection, antibiotics are the primary treatment. Early treatment is crucial to reduce the severity of the illness and to prevent spreading it to others. Infants under one year often require hospitalization to monitor their breathing and receive supportive care, such as oxygen and IV fluids.
When to See a Doctor or Go to the ER
Trust your instincts. If you are concerned about your child's breathing, seek medical care.
Call your pediatrician if your child:
- Has a cough that is worsening or lasts more than a week.
- Has a high fever (over 100.4°F) along with a severe cough.
- Is having coughing spells that cause vomiting.
- Shows signs of dehydration from not drinking enough.
Go to the emergency room or call 911 immediately if your child:
- Is struggling to breathe. Look for chest retractions (skin pulling in between the ribs), nasal flaring, or stridor while at rest.
- Shows any signs of cyanosis (bluish or purplish skin, lips, or tongue).
- Has pauses in their breathing (apnea).
- Is extremely lethargic or difficult to wake up.
- Is drooling or unable to swallow.
Recovery and Potential Long-Term Effects
The recovery paths for these two illnesses are vastly different and highlight the seriousness of whooping cough.
Croup's Quick Recovery
Most children with croup recover fully within three to five days with no lasting effects. The symptoms, while scary, are usually short-lived.
Whooping Cough's Long Road to Recovery
Recovery from whooping cough can be a long and slow process, sometimes taking months. While most people make a full recovery, severe pertussis, especially in infants, can lead to life-threatening and permanent complications, including:
- Pneumonia
- Seizures
- Brain damage due to lack of oxygen
- Chronic lung problems
This high risk of severe complications is why on-time vaccination with the DTaP (for children) and Tdap (for adolescents and adults) vaccines is so critically important.
Frequently Asked Questions (FAQ)
What is the main difference in sound between a croup cough and a whooping cough?
The most distinct difference is the sound. Croup causes a harsh, 'barking' cough, often compared to the sound of a seal. Whooping cough (pertussis) is characterized by long, severe coughing fits that end with a high-pitched 'whoop' sound as the person gasps for air. However, the 'whoop' may be absent, especially in infants.
Which is more dangerous, croup or whooping cough?
Whooping cough (pertussis) is generally more dangerous than croup. It is a bacterial infection that can lead to severe complications, especially in infants under one year old, including pneumonia, seizures, brain damage, and can even be fatal. Croup is a viral illness that is typically milder and resolves within a week, with serious complications being rare.
Can adults get croup or whooping cough?
Yes, adults can get both, but presentations differ. Whooping cough in adults often manifests as a severe, persistent cough that lasts for weeks or months, usually without the 'whoop' sound. Croup is rare in adults because their airways are larger and less susceptible to the significant narrowing that causes severe symptoms in children.
Are croup and RSV the same thing?
No, they are not the same. Croup is a condition—an inflammation of the upper airways—that results in a barking cough. RSV (Respiratory Syncytial Virus) is a specific type of virus. RSV is one of the many viruses that can cause croup, but it can also cause other respiratory illnesses like bronchiolitis and pneumonia.
References
- Stony Brook Medicine: Croup vs. Whooping Cough: What Parents Should Know
- Orlando Health: Is It Croup or Whooping Cough?
- Medical News Today: Whooping cough vs. croup: Differences and more
- Cleveland Clinic: Croup: Causes, Symptoms & Treatment
- Centers for Disease Control and Prevention (CDC): Pertussis (Whooping Cough)
About the author
Aisha Khan, MD, is a board-certified pediatrician with a focus on adolescent medicine and developmental disorders. She runs a private practice in Austin, Texas, and is a vocal advocate for child mental health services.