Whooping Cough Symptoms and Signs

Whooping cough, also known as pertussis, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis1 . It affects people of all ages but is especially dangerous for infants and young children, who are at higher risk of severe complications2 . The illness typically begins with mild cold-like symptoms and progresses to intense coughing fits that can last for weeks or even months3 .

Key Whooping Cough Symptoms

Whooping cough often starts with symptoms similar to a common cold, making early diagnosis challenging3 . Initial signs include a runny or stuffy nose, sneezing, mild cough, low-grade fever, and watery eyes3 . After one to two weeks, the cough worsens, becoming severe and uncontrollable, often occurring in fits called paroxysms1 . These coughing fits can be so intense that they cause vomiting, exhaustion, and a distinctive high-pitched "whoop" sound during the next breath of air3 . However, not everyone with whooping cough makes the whooping sound; it is less common in adults and infants3 .

In infants, symptoms may differ significantly. Many babies do not cough but instead experience apnea, which are life-threatening pauses in breathing, sometimes accompanied by cyanosis (blue or purple skin due to lack of oxygen) 3. Other signs in infants include difficulty breathing, gagging, and struggling to feed1 .

Common symptoms across age groups include:

Runny or stuffy nose and sneezing3
Mild or occasional cough progressing to severe coughing fits3
Low-grade fever or normal temperature3
High-pitched whooping sound after coughing fits (more common in children) 3
Vomiting following coughing episodes1
Exhaustion and difficulty sleeping due to coughing1
Apnea and cyanosis in infants3

💡 Did You Know?
Whooping cough is caused by bacteria and spreads easily through coughing and sneezing droplets4 .

Whooping Cough Stages and Symptoms

Whooping cough progresses through three distinct stages: the catarrhal phase, the paroxysmal phase, and the convalescent phase5 . Each stage has characteristic symptoms and durations.

Catarrhal Phase

The catarrhal phase lasts about 1 to 2 weeks and resembles a common cold5 . Symptoms are nonspecific and include:

Runny nose (rhinorrhea) 6
Sneezing6
Nasal congestion7
Low-grade fever (usually less than 100.4°F or 38°C) 3
Mild, occasional cough that gradually worsens7

This phase is the most contagious period of the illness, as the bacteria multiply and spread easily through respiratory droplets8 . Infants may exhibit apnea during this phase, sometimes without the typical cough2 . Early antibiotic treatment during the catarrhal phase can reduce the severity of symptoms and shorten the contagious period9 .

Paroxysmal Phase

The paroxysmal phase typically lasts 1 to 6 weeks but can extend beyond 10 weeks in some cases6 3. It is marked by severe coughing fits known as paroxysms, which are the hallmark of pertussis6 . Key features include:

Frequent, rapid coughing spells lasting several minutes2
A high-pitched "whoop" sound during the inspiratory gasp after coughing fits, especially in children7
Post-tussive vomiting (vomiting after coughing) 7
Cyanosis (bluish discoloration of the face) due to oxygen deprivation during coughing fits2
Exhaustion and difficulty sleeping1
Coughing fits triggered by eating, crying, or laughing10

In infants, the whoop may be absent due to weak respiratory muscles, and apnea or respiratory distress may be more prominent11 . The paroxysmal phase is less severe in vaccinated individuals, who may experience milder symptoms or a prolonged cough without the classic whoop2 .

Convalescent Phase

The convalescent phase involves gradual recovery and can last several weeks to months6 . During this stage:

The frequency and severity of coughing fits decrease6
Mild, occasional coughing may persist for weeks or months7
Paroxysms may recur with subsequent respiratory infections2
Patients remain vulnerable to other respiratory illnesses during recovery1

Although symptoms improve, the cough may linger, sometimes called the "100-day cough" due to its prolonged nature1 .

Stage	Duration	Key Symptoms	Contagiousness
Catarrhal	1–2 weeks	Cold-like symptoms, mild cough, sneezing	Highest
Paroxysmal	1–6+ weeks	Severe coughing fits, whooping, vomiting	Reduced with antibiotics
Convalescent	Weeks to months	Gradual symptom resolution, persistent cough	Low
Sources: 1235

Whooping Cough in Children

Children typically progress through the three classic stages of pertussis: catarrhal, paroxysmal, and convalescent5 . During the catarrhal stage, children exhibit mild respiratory symptoms such as rhinorrhea, sneezing, nasal congestion, conjunctival suffusion (red eyes), and low-grade fever7 . This phase is highly contagious7 .

The paroxysmal stage is characterized by the disappearance of catarrhal symptoms and the onset of severe coughing fits7 . These fits may cause vomiting, exhaustion, and the characteristic inspiratory whoop sound7 . The coughing fits can be triggered by feeding, crying, or playing10 . The duration of this stage ranges from 1 to 6 weeks or longer6 .

Whooping cough is often mistaken for a common cold in its early stages, making early diagnosis difficult. The disease is most contagious before the severe coughing fits begin, underscoring the importance of early medical attention and vaccination3 8.

The convalescent stage involves a gradual reduction in coughing severity and frequency, but the cough may persist for months7 . Early antibiotic treatment can reduce the severity and duration of symptoms and shorten the contagious period, which otherwise lasts about 21 days without treatment9 .

Children who are unvaccinated or incompletely vaccinated are at higher risk of severe illness and complications2 . Complications in children can include pneumonia, seizures, rib fractures from severe coughing, and, rarely, encephalopathy (brain disease) 2.

Mild respiratory symptoms in early stage7
Severe coughing fits with whooping and vomiting7
Prolonged cough lasting weeks to months7
Early antibiotic treatment reduces severity and contagiousness9
Higher risk of complications in unvaccinated children2

“Pertussis can cause serious and deadly complications in infants. In infants younger than 12 months who get pertussis, about a third need treatment in a hospital. Hospitalization is most common in infants younger than 6 months.”
— Guo et al., 202411

When to See a Doctor

Infants under 6 months old are at the highest risk for severe complications from whooping cough, including apnea, pneumonia, pulmonary hypertension, seizures, and death11 . Unlike older children and adults, infants often do not present with the classic whooping cough but instead show signs of respiratory distress such as tachypnea (rapid breathing), labored breathing, and cyanosis11 .

Urgent medical attention is needed if an infant or child exhibits:

Difficulty breathing or apnea (pauses in breathing) 11
Cyanosis (blue or purple discoloration of skin or lips) 11
Severe coughing fits causing vomiting or exhaustion3
Signs of dehydration such as decreased urination or lethargy1
Seizures or altered mental status11

Vaccination with DTaP in infancy and maternal Tdap during pregnancy are critical preventive measures to reduce the risk of severe pertussis in infants11 9. Early antibiotic treatment not only shortens the contagious period but can also reduce symptom severity9 .

Infants may have atypical symptoms like apnea rather than cough11
Respiratory distress signs require immediate evaluation11
Severe complications are most common in infants under 6 months11
Vaccination is key for prevention11 9
Early treatment reduces transmission and complications9

💡 Did You Know?
Infants with severe pertussis may develop life-threatening complications such as pulmonary hypertension and encephalopathy11 .

Whooping Cough Summary

Whooping cough is a contagious respiratory infection caused by Bordetella pertussis9 . It spreads through respiratory droplets when an infected person coughs or sneezes and is highly contagious, with about 8 out of 10 non-immune individuals becoming infected after exposure8 . The illness progresses through three stages: catarrhal, paroxysmal, and convalescent, with symptoms ranging from mild cold-like signs to severe coughing fits5 .

Antibiotic treatment is most effective when started early in the catarrhal phase, reducing symptom severity and contagiousness9 . However, the characteristic cough can persist for weeks to months even after treatment7 . Infants, especially those under 6 months, are at the greatest risk for severe complications and require urgent medical care11 .

Vaccination with DTaP in childhood and Tdap boosters in adolescents, adults, and pregnant women remains the most effective way to prevent pertussis and its complications9 2. Good hygiene practices and early treatment of exposed individuals help control the spread of infection8 .