Patient education: Croup in infants and children (Beyond the Basics)

WHAT IS CROUP? — 

Croup is a common respiratory illness in young children. It is caused by viruses that produce inflammation and swelling in the larynx (voice box) and upper trachea (windpipe) (figure 1). This narrows the space available for air to enter the lungs (figure 2) and causes the typical signs and symptoms of croup, which include hoarseness, a barking cough, and stridor (noisy high-pitched breathing). (See 'Croup symptoms' below.)

Croup mostly occurs in infants and young children between six months and three years of age. It is uncommon in children older than six years. Most cases occur in the fall and early winter months.

The most common cause of croup is the parainfluenza virus. Other viruses that sometimes cause croup include influenza, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus that causes coronavirus disease 2019 [COVID-19]), rhinovirus (the virus that causes the common cold), respiratory syncytial virus (RSV), and adenoviruses. These viruses are common causes of upper respiratory infections in children, and they do not always cause croup.

Bacterial infection of the same area (which is called bacterial tracheitis) is a rare complication of croup that can occur during or following viral croup. Bacterial tracheitis is a more severe illness and requires a different treatment than viral croup.

CROUP SYMPTOMS — 

The primary symptoms of croup are a "barking cough," hoarseness, and stridor (which is a high-pitched sound heard when breathing in).

●Cough and congestion – Symptoms usually start gradually, beginning with nasal stuffiness, runny nose, and fever, followed by development of the characteristic barking cough.

●Fever – Most children with croup have fevers, which may be low-grade (99 to 101°F [37.3 to 38.3°C) or as high as 104°F (40.5°C). The table provides information on how to take a child's temperature (table 1). (See "Patient education: Fever in children (The Basics)".)

●Other signs of viral illness – Depending upon the virus causing the illness, some children may develop other signs of viral illness such as a rash, pink eye (conjunctivitis), or swollen lymph nodes. Dehydration can occur if the child is not able to drink enough fluids.

●Breathing difficulty – Most children with croup have only mild symptoms (barking cough without breathing difficulties) and the illness lasts only a few days (see 'Croup's typical course' below). However, some children may develop difficulty breathing that can worsen during the 12 to 48 hours after the onset of symptoms. These breathing symptoms tend to worsen at night.

As the airway narrows, noisy high-pitched breathing (called stridor) develops. The child may show other signs of respiratory distress such as fast breathing and retractions (caving in of the skin and muscles between the ribs and below the ribcage) (figure 3). Children with severe respiratory distress may become restless, anxious, or agitated, which can further increase the airway narrowing making it even more difficult to breathe.

In the most severe cases in which the airway narrowing is very severe, croup can be life-threatening, but this is rare. In these cases, the child may develop blue-tinged skin (called cyanosis) because they are not able to get enough air into their lungs. Cyanosis may first be noticed in the fingers and toenails; ear lobes; tip of the nose, lips, and tongue; and inside of the cheek.

CROUP DIAGNOSIS — 

Croup is usually diagnosed based upon the child's symptoms and signs, including a barking cough and stridor. X-rays and laboratory testing usually are not needed to make the diagnosis.

CROUP TREATMENT — 

The treatment of croup depends upon the severity of symptoms and the risk of rapid worsening. Children with mild symptoms who have no risk factors for developing severe croup generally are treated at home, while a child with moderate to severe symptoms or who is at risk for rapid worsening should be treated in an emergency department. Regardless of severity, it is important to keep the child calm since agitation and crying can worsen the symptoms.

Mild croup — Most children with croup have mild symptoms (congestion and barking cough without stridor or respiratory distress). Children with mild croup are usually treated at home.

Home management — Supportive care at home includes:

●Mist therapy or cool air – Mist therapy can be provided from a humidifier or sitting with the child in a bathroom (not in the shower) filled with steam generated by running hot water from the shower. Hot steam humidifiers should be avoided because of the risk of burns. A parent should stay with the child during mist treatment; a favorite book or lullaby may help to keep the child calm.

Another option is to allow the child to breathe cool night air during by opening a window or door.

●Fever reduction – Fever can be treated with over-the-counter medications such as acetaminophen or ibuprofen. (See "Patient education: Fever in children (Beyond the Basics)".)

●Encourage fluids – Warm, clear fluids may help to sooth the inflamed throat and vocal cords. Warm water or juice are safe for children older than four months. Frozen juice popsicles also can be given.

●Keep child's head propped up – While sleeping, a child may be propped up in bed with an extra pillow. Pillows should not be used with infants younger than 12 months of age.

●Avoid smoke exposure – Smoking in the home should be avoided; smoke can worsen a child's cough.

●Monitor for worsening symptoms – Parents/caregivers may sleep in the same room with their child during an episode of croup so that they will be immediately available if the child begins to have difficulty breathing.

If the child's symptoms worsen (if they develop noisy breathing [stridor] that doesn't improve with mist therapy, retractions [caving in of the skin and muscles between the ribs and below the ribcage (figure 3)], or rapid or labored breathing), the parent/caregiver should seek immediate medical attention. (See 'When to seek help' below.)

Management in the health care setting — A child with mild croup who is seen in a health care provider's office or the emergency department is generally managed with the same supportive care measures that are used at home (mist therapy, medicines to reduce fever, encouraging fluid intake). In addition, the health care provider may give a single dose of a glucocorticoid medication. The most frequently used glucocorticoids are dexamethasone and prednisolone. These medications are usually administered as a liquid taken by mouth. Dexamethasone can also be given intravenously (IV) or with an intramuscular (IM) injection, especially if the child is vomiting and not able to keep liquids down. Less commonly, an inhaled glucocorticoid, budesonide, may be given if a child is unable to keep liquids down and does not have an IV.

Glucocorticoid medications such as dexamethasone, prednisolone, or budesonide work by decreasing inflammation in the airway. They typically start to work within four to six hours after the dose is given. For a child with mild croup, glucocorticoids may reduce the need for a repeat visit to the emergency department or provider's office.

Moderate to severe croup — Signs of moderate to severe croup include retractions (caving in of the skin and muscles between the ribs and below the ribcage (figure 3)), rapid or labored breathing, and stridor (noisy high-pitched breathing) that is heard even when the child is resting.

Children with moderate to severe croup should be evaluated in an emergency department or clinic capable of managing urgent respiratory illnesses. Severe croup is a potentially life-threatening illness, and treatment should not be delayed for any reason.

The treatment of moderate to severe croup usually includes the following:

●Medications to reduce airway swelling – This includes a glucocorticoid medication (dexamethasone) and inhaled epinephrine. (See 'Dexamethasone' below and 'Inhaled epinephrine' below.)

●IV fluid therapy – This may be needed if the child is dehydrated as a result of fever or rapid breathing, both of which increase the body's loss of fluids. Difficulty breathing can prevent a child from eating and drinking, which increases the risk of dehydration.

●Monitoring – This includes monitoring of oxygen levels, breathing, heart rate, and level of alertness, which are used to assess the child's status and response to treatment.

●Oxygen therapy – If the child's oxygen level is low, they will be given oxygen therapy. This is usually given by placing a tube (called a nasal cannula) under a child's nose or by placing a face mask over the nose and mouth. For children with more severe symptoms, many hospitals use a form of oxygen therapy called "high flow." High flow delivers oxygen at a high rate through a nasal cannula, which may help the infant breath more comfortably. Placement of a breathing tube in the throat (called "intubation") is rarely needed for children with severe croup; less than 1 percent of children seen in the emergency department for croup require intubation.

●Mist therapy – Humidified air is sometimes used in the treatment of moderate to severe croup, although it is unclear whether it is beneficial. Mist therapy may provide a sense of comfort to the child. However, if the child is instead agitated by the mist, it is usually discontinued.

Dexamethasone — Dexamethasone is the preferred glucocorticoid medication for treating moderate to severe croup. It is a long-acting medication that works by decreasing inflammation in the airway. It starts to work within four to six hours of the first dose.

Dexamethasone has been shown to reduce signs of respiratory distress in children with croup. It also reduces the need for hospital admission and decreases the duration of the stay in the hospital.

Dexamethasone can be given by mouth or as an IV or IM injection (depending upon which treatment is easiest for the child). Most children only require one dose. Serious side effects are rare.

Inhaled epinephrine — Inhaled epinephrine is given by nebulizer (an inhaled mist) to children with moderate to severe croup. It is a quick-acting medication that can rapidly reduce airway swelling. The effect is short-lived, lasting only two hours or less. Retreatment may be needed.

The most common side effect of epinephrine is rapid heart rate. Serious side effects are rare.

Children who are given epinephrine must be monitored for two to four hours after the last dose to ensure that their symptoms do not return.

Other therapies — Other therapies, such as antibiotics, cough medicines, and decongestants are not routinely recommended for children with croup. Antibiotics do not play a role in treating croup because croup is caused by viruses and antibiotics do not treat viruses. Cough medicines and decongestants are generally not helpful and should not be used in children under the age of 6 years. (See "Patient education: Cough in children (The Basics)".).

CROUP'S TYPICAL COURSE — 

Symptoms of croup resolve in most children within two days, but the cough can persist up to one week. Complications are uncommon.

Approximately 5 to 10 percent of children with croup who are seen in the emergency department require hospitalization. The most common reasons for hospitalization are:

●Oxygen therapy is needed to keep the child's oxygen levels in a safe range

●Croup is complicated by severe dehydration requiring intravenous fluid therapy

●Multiple doses of inhaled epinephrine are needed to provide relief

●Severe symptoms persist despite initial treatment, especially if the child's breathing becomes fatigued

For children requiring hospitalization, some may require observation for only a few hours to half a day. Others may stay in the hospital for a day or two. It is unusual to require more than a two-day hospitalization for croup. If this happens, an additional evaluation may be performed to assess for other causes of stridor and breathing difficulty. This may include X-rays and/or consultation with an ear, nose, throat specialist.

CONTAGIOUSNESS — 

The viruses that cause croup can be spread easily through coughing and sneezing. Children with croup should be considered contagious for three days after the illness begins or until the fever is gone.

CROUP PREVENTION — 

Simple hygiene measures can help to prevent infection with the viruses that lead to croup.

Hygiene and other preventive measures include:

●Frequently wash hands with soap and water – Hands should ideally be wet with water and plain or antimicrobial soap and rubbed together for 15 to 30 seconds. Special attention should be paid to the fingernails, between the fingers, and the wrists. Hands should be rinsed thoroughly and dried with a single-use towel.

●Use alcohol-based hand rubs – These are a good alternative for disinfecting hands if a sink is not available. Hand rubs should be spread over the entire surface of hands, fingers, and wrists until dry and may be used several times. Hand rubs are available as a liquid or wipe in small, portable sizes that are easy to carry in a pocket or handbag. When a sink is available, visibly soiled hands should be washed with soap and water.

●Avoid close contact with other adults and children with upper respiratory infection when possible – This may be difficult, especially when in public, but parents/caregivers can try to limit direct contact. In addition, infants or children who are sick should not be sent to daycare or school, as this can spread the illness to others.

●Ensure the child is vaccinated – There are no vaccines against the most common virus that cause croup (parainfluenza virus). However, vaccines are recommended for other viruses that can cause croup (influenza, COVID-19, and measles). (See "Patient education: Influenza prevention (Beyond the Basics)" and "Patient education: COVID-19 vaccines (The Basics)" and "Patient education: Measles, mumps, and rubella vaccine (The Basics)".)

WHEN TO SEEK HELP — 

Parents/caregivers should seek immediate medical attention if a child develops features of worsening or severe croup. This includes:

●Rapid or labored breathing

●Retractions (caving in of the skin and muscles between the ribs and below the ribcage ) (figure 3)

●Stridor (noisy high-pitched breathing) while resting

●Pale or blue-tinged skin

●Drooling or difficulty swallowing

●Inability to speak or cry due to difficulty taking a breath

●Severe agitation or fatigue from labored breathing

Parents/caregivers should not attempt to drive their child to the hospital if the child is severely agitated, has blue-tinged skin, is struggling to breathe, or is excessively drowsy (lethargic); emergency medical services should be called, available in most areas of the United States by dialing 911.

A parent/caregiver should call their child's health care provider if:

●A fever (temperature higher than 100.4°F or 38°C) lasts more than three days

●Symptoms of mild croup last longer than seven days

●There are questions or concerns about the child's condition

WHERE TO GET MORE INFORMATION — 

Your child's health care provider is the best source of information for questions and concerns related to your child's medical problem.

This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Croup (The Basics)
Patient education: Cough in children (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Fever in children (Beyond the Basics)
Patient education: Influenza symptoms and treatment (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Approach to chronic cough in children
Croup: Management
Assessment of stridor in children
Causes of chronic cough in children
Croup: Clinical features, evaluation, and diagnosis
Emergency evaluation of acute upper airway obstruction in children
Common causes of hoarseness in children
Parainfluenza viruses in children

The following organizations also provide reliable health information.

●National Library of Medicine

(www.nlm.nih.gov/MEDLINEPLUS/ency/article/000959.htm, available in Spanish)

●American Academy of Pediatrics

(www.healthychildren.org/English/health-issues/conditions/chest-lungs/pages/Croup.aspx)

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