A bacterial infection, also called whooping cough, that causes bouts of coughing
Pertussis is a distressing and extremely infectious disease that is caused by the Bordetella pertussis bacterium, which infects and inflames the trachea (windpipe) and the bronchi (airways) in the lungs. The bacteria are transmitted in the airborne droplets that are produced when infected people cough and sneeze. Pertussis brings about violent fits of coughing that often end in a characteristic, high-pitched “whoop” when the affected person inhales.
Pertussis is most serious in children under the age of 12 months, when the disease can be life-threatening. Before the introduction of a reliable vaccine, pertussis was responsible for a considerable proportion of childhood deaths in the UK.
The first symptoms usually appear 2–3 weeks after infection. They are mild and resemble those of a common cold, typically a dry cough, runny nose, and sneezing. During this initial stage, lasting about 7–14 days, the disease is highly infectious. Following this period, symptoms worsen and may include:
Attacks of coughing followed by a sharp intake of breath that may produce a whooping sound. Coughing bouts are often much worse at night.
Production of large amounts of sputum during coughing fits.
Vomiting, which is caused by severe, repeated fits of coughing.
Episodes of prolonged coughing may cause small blood vessels to burst, resulting in a rash of small, flat, red spots, especially around the face, hairline, and eyes. Nosebleeds may also occur if vessels in the nose burst.
Complications of pertussis include pneumonia and bronchiectasis, in which the airways become abnormally widened. Infants may stop breathing temporarily after a severe coughing spasm, which may result in a lack of oxygen that may cause seizures and brain damage.
The doctor will usually be able to diagnose pertussis from the symptoms. In some cases it may be necessary to confirm the diagnosis by taking a throat swab and culturing it to check for the causative bacterium or by taking a blood sample to check for antibodies to the bacterium.
The treatment of pertussis varies according to the age of the person affected and the stage of the disease.
Babies and children under 5 years old may sometimes be treated at home but often need treatment in hospital because the infection is more serious for this age group. There, they may be given antibiotics intravenously, and may also be given intravenous fluids. If they are having breathing difficulties, they may also be given corticosteroid drugs, and possibly oxygen therapy.
Older children and adults can usually be treated at home. If the infection is diagnosed in its early stages, your doctor will probably prescribe antibiotics. The drugs will stop the person from being infectious after he or she has been taking them for 5 days; without antibiotics, the person may still be infectious until 3 weeks after the coughing bouts started. If pertussis is not diagnosed until the later stages, antibiotics will probably not be prescribed because the bacterium is no longer in the body and the person is no longer infectious. If treated at home, the person should get plenty of rest, keep warm, drink plenty of fluids, and stay away from others until he or she is no longer infectious. To prevent the infection from spreading, antibiotics may also be prescribed for people who have been in close contact with an infected person.
The symptoms of pertussis usually improve within 4–10 weeks if there are no complications, but a dry cough may persist for months.
The pertussis vaccine is part of the routine childhood immunization programme in the UK. It is given as part of the diphtheria, pertussis, tetanus, polio, and Haemophilus influenzae type b combined vaccine at 2, 3, and 4 months old. A booster dose is given as part of the diphtheria, pertussis, tetanus, and polio combined vaccine before starting school, at between 3 years 4 months and 5 years of age. Your child should receive the full course of immunization.
Pertussis is most dangerous in infants, including those too young to be immunized. Older siblings and parents may infect younger children. It is therefore important to maintain a high level of immunity to protect infants. Reactions to the vaccine are rare; the disease itself, which can cause brain damage and death, presents a far greater risk than any possible risk from the vaccine.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.