What Causes Croup?

What Causes Croup?

Croup is a common respiratory problem prevailing in young children that tends to develop in the fall or winter. It describes a deep and barking cough that is caused by an upper respiratory infection that blocks a child's ability to breathe. Its characteristic symptom is harsh coughing which sounds like a bark. Croup causes swelling and narrowing in the voice box, windpipe, and breathing tubes which lead to the lungs, and this makes it difficult for the child to breathe.

Croup is an acute infectious childhood condition of the upper respiratory tract, which involves the larynx (vocal cords), trachea (windpipe), and in some cases, the upper airways of the lungs. Inflammation of the bronchial tubes, vocal cords and windpipe result in coughing and other symptoms of the condition. The sound of a seal barking is the result of a cough forcing air through swollen vocal cords. When a child has croup, he or she may produce a high-pitched whistling sound while breathing due to narrowed passageways.

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Croup most commonly occurs in children who are aged between six months and three years old and becomes very rare in children above the age of six. Croup is highly contagious, particularly during the first few days of the infection. It can be passed on when children with the infection sneeze or cough. It may also spread through infected mucus, contaminated objects such as toys, and other surfaces. Almost all cases of croup are mild, but it could still progress and cause harm to children. Children suffering from croup can easily get better after several days with proper rest and care at home.

It must be noted that croup is highly contagious. The germs that cause it can be passed from one person to another through coughing and sneezing and through close contact. To effectively avoid developing croup, practice regular hand washing and have limited contact with children who have the disease. As children grow older and their lungs and windpipes mature, they are less likely to get croup. Moreover, getting a flu vaccine each year may help your child avoid a number of viruses that can lead to the infection.

The Cause of Croup

Croup is usually the result of a virus, and it is usually a flu virus. The human parainfluenza virus accounts for 80 percent of all croup cases. The human parainfluenza virus 1 (HPIV-1) is the leading cause of the condition. Types 1 and 2 of the parainfluenza virus are responsible for around 66 percent of croup cases, while a type 4 parainfluenza virus is linked to milder illnesses. Some studies show that influenza A and B, respiratory syncytial virus (RSV), adenovirus, metapneumovirus, mycoplasma, and coronavirus are the causes for the remaining croup cases.

Viruses are contracted through airborne droplets. For example, if an infected child coughs or sneezes, another child can be infected with such virus. The virus living in these droplets can survive and stay on objects including toys and other materials. The infection tends to spread when a child touches a surface that has been contaminated with droplets and then touches his or her eyes, nose or mouth. The parents must, therefore, be careful to maintain the cleanliness of their surroundings with proper hygiene and care. Another cause of croup may be a bacterial infection that was the result of a viral infection. The viral infection in croup takes the following course:

  • The virus first infects the nose and throat.
  • The virus spreads and goes down to the respiratory tract towards the larynx and trachea.
  • The upper portion of the trachea swells when the infection progresses.
  • The bronchi will become narrow.
  • As the airway narrows, children breathe more deeply and quickly, which will then lead to the development of croup symptoms.
  • When breathing becomes difficult, it is expected that your child will become agitated or restless. Agitation also causes a narrowing of the airway, which can also lead to more breathing difficulties that will further aggravate the condition. With an increased difficulty in breathing, the child will become tired as breathing becomes harder and faster. In severe cases, the child will be unable to breathe on his or her own.

Signs and Symptoms of Croup

Croup often develops from a regular cold virus. Inflammation in the upper respiratory tract causing coughing, and due to swollen vocal cords and passageways, a child will experience a loud barking cough. The cough typically becomes worse at night, and crying, coughing, agitation and stress can worsen the condition. Other common symptoms include a fever and a hoarse voice. Croup causes a child's breathing to be noisy and labored. Since children have small airways to begin with, they are more prone to croup which is the result of swelling in the airways. Symptoms are especially harsher in children under three years old. Croup usually lasts for three to five days. Some common signs of this infection are:

  • Harsh, barking cough
  • Difficulty in breathing
  • Stridor (high-pitched sound)
  • Fever
  • Hoarse voice

How is Croup Diagnosed?

Croup can be diagnosed by observing the child’s breathing pattern, examining the throat, and listening to the chest with the use of a stethoscope. Other tests are not required but may be done to rule out other underlying conditions. The doctor can tell if the child has croup based on the child's symptoms and physical exam. The majority of croup cases are treated effectively through self-care measures at home. Croup typically resolves on its own after three to six days. Thus, medical treatment is not often required.

Babies and children with croup must be kept at home and away from others during the first few days of the illness as the infection is very contagious during these times. They must be isolated until they feel better. In rare cases, the doctor may place a small clip called a pulse oximeter on your child's finger, toe, or earlobe to make sure that there is enough oxygen in the body.

An important thing to do to prevent the spread of infection is to wash your hands frequently. Moreover, avoid having close contact with people who have respiratory infections. Vaccines for measles, diphtheria, and Haemophilus influenzae can also protect children from the severe types of croup.

It is important to have a treatment plan by getting in touch with a medical expert.