Is Whooping Cough (Pertussis) Hard To Diagnose?

Whooping cough, also known as pertussis, is a contagious and serious respiratory illness caused by the bacteria Bordetella pertussis. Classic symptoms include intense, long-lasting coughing that can cause vomiting and a "whoop" noise when you inhale or gasp for air after coughing.

An early whooping cough diagnosis can help prevent the spread of infection, while early treatment can shorten the duration of symptoms. However, a diagnosis may be difficult because whooping cough symptoms are similar to those of other respiratory infections. One study found that, on average, people had two missed opportunities for whooping cough diagnosis and a delay in diagnosis of about 12 days.

Healthcare providers can diagnose whooping cough by evaluating your signs and symptoms, reviewing your medical history, and completing certain laboratory and imaging tests.

Signs and Symptoms

Whooping cough symptoms vary based on your age and whether you have been vaccinated against pertussis. Symptoms are typically milder in people who have received the vaccination that protects against whooping cough.

Whooping cough symptoms often begin like the common cold. Unlike a common cold, coughing symptoms can last weeks or months.

Early symptoms of whooping cough often include a runny or stuffed nose, low-grade fever, and an occasional cough. This early stage is usually the most infectious time and can last 1-2 weeks. The fever often goes away as time passes (by about 7-10 days later), but you may develop "coughing fits" that worsen over time. Coughing fits can lead you to:

• Vomit during or after coughing
• Feel extremely tired after coughing
• Make a high-pitched "whoop" sound when you inhale
• Have trouble sleeping
• Have difficulty breathing
• Temporarily stop breathing (known as apnea), especially in infants and young children

These severe coughing symptoms are more likely to occur overnight and can last as long as 10 weeks. Symptoms typically slowly improve over time.

The "whooping" sound is not always present, but it is one of the most common ways for a healthcare provider to diagnose the illness. One study found that the presence of the "whooping" sound and vomiting are the two symptoms most likely to lead to a diagnosis of whooping cough in adults. In children, vomiting after coughing is less helpful in diagnosing whooping cough.

If you experience more than one of the symptoms listed above or your physical exam shows signs of an active infection, your healthcare provider will likely consider diagnosing and treating whooping cough.

Medical History

Your healthcare provider will consider your past medical history when diagnosing you with whooping cough. Risk factors for developing whooping cough or experiencing more severe symptoms include:

• Not being vaccinated against whooping cough
• Being younger than 1 year old
• Pregnancy
• Preexisting medical conditions, such as immunocompromising conditions (weakened immunity), asthma, or chronic obstructive pulmonary disease (COPD)

Whooping cough is spread from person to person through respiratory droplets, and symptoms usually develop within 5-10 days of exposure. If you have been in close contact with someone who has whooping cough, it is important to share this information with your healthcare provider.

Laboratory and Imaging Tests

Your healthcare provider may ask for a mucus sample from the back of your throat to test for whooping cough. They may also swab your throat or nose to test for evidence of the whooping cough bacteria. These tests usually take multiple days to provide accurate results.

A blood sample can also be taken to test for signs of an infection. There are no blood tests specific to whooping cough. However, your healthcare provider can evaluate certain labs to help determine if your body is fighting off an active infection.

They can also test your blood to determine if you have certain levels of antibodies related to the whooping cough bacteria. Antibodies are proteins produced by your immune system to protect you against infections. If you have received the whooping cough vaccine, your body already has whooping cough antibodies, which may affect your results.

Your healthcare provider may also perform a chest X-ray to look for lung inflammation, fluid, or infection. However, this test is not specific enough to diagnose whooping cough.

Screening for Related Conditions

Whooping cough can look extremely similar to other respiratory infections. Respiratory infections with similar symptoms include:

• Other bacterial respiratory infections, like pneumonia (lung fluid and inflammation) and tuberculosis (an airborne bacterial infection that commonly affects lungs)
• Viral respiratory infections, like COVID-19 and influenza (the flu)
• Reactive airway diseases, like asthma and COPD
• A foreign body in your throat (something stuck in your throat)
• Seasonal allergies

Your healthcare provider will ask for your medical history, complete a physical exam, and order various laboratory and imaging tests to help determine which medical condition could be causing your symptoms.

A Quick Review

Whooping cough, or pertussis, is a contagious and serious respiratory illness caused by the bacteria Bordetella pertussis. Classic symptoms of whooping cough include intense coughing, which may lead to vomiting, and a "whoop" noise when you inhale or gasp for air after coughing.

An early whooping cough diagnosis is important to help prevent the spread of infection and to start antibiotic treatment. However, the infection is similar to other respiratory infections, and a diagnosis may be difficult. You can protect yourself from whooping cough by receiving the whooping cough vaccine.

Talk with your healthcare provider if you believe you may have a whooping cough infection. They can evaluate your signs and symptoms, review your medical history, and complete certain laboratory and imaging tests to help determine whether or not you have pertussis.