Table of ContentsView AllTable of ContentsHow Long Is Croup Contagious?TransmissionSymptomsSeeking Immediate CarePrevention
Table of ContentsView All
View All
Table of Contents
How Long Is Croup Contagious?
Transmission
Symptoms
Seeking Immediate Care
Prevention
Croup is a contagious upper respiratory tract infection that can cause airway swelling and a hoarse, barking-like cough. Croup is most common in children aged between 3 months and 5 years. However, anyone can become infected.
Croup leads to swelling around the vocal cords and windpipe. Typically, children recover from croup on their own in three days to a week.
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Croup is contagious for the first three days after symptoms start—or until the infected person has been fever-free for 24 hours.While the person is contagious, they can easily infect others.
Though not everyone who gets infected will develop croup, it’s still a common illness among children between 6 months and 3 years old. Avoid taking your child to school or daycare if they may spread croup to others.
In general, after three days or an absence of fever, normal activities can be resumed.However, every child is different. Monitor symptoms and consult with your pediatrician or primary care provider when unsure. Some symptoms, like coughing, can persist, making it more challenging to return to all normal activities.
Fever in Children With CroupWhile most children develop a fever with croup, some children never do.Younger children experience a fever at lower temperatures than adults.Feveris considered to be a temperature as follows:100.4 F (38 C) or higher in children under 3 months old if measured rectally or on the forehead99 F (37.2 C) or higher in children under 3 months old if measured in the armpit102 F (38.9 C) or higher in children between 3 months and 3 years old if measured rectally, on the forehead, or in the ear101 F (38.3 C) or higher in children between 3 months and 3 years old if measured in the armpit104 F (40 C) or higher in children of any age
Fever in Children With Croup
While most children develop a fever with croup, some children never do.Younger children experience a fever at lower temperatures than adults.Feveris considered to be a temperature as follows:100.4 F (38 C) or higher in children under 3 months old if measured rectally or on the forehead99 F (37.2 C) or higher in children under 3 months old if measured in the armpit102 F (38.9 C) or higher in children between 3 months and 3 years old if measured rectally, on the forehead, or in the ear101 F (38.3 C) or higher in children between 3 months and 3 years old if measured in the armpit104 F (40 C) or higher in children of any age
While most children develop a fever with croup, some children never do.Younger children experience a fever at lower temperatures than adults.Feveris considered to be a temperature as follows:
A parainfluenza virus causes the majority of croup cases, typically in the fall and early winter.
Importantly, having a croup infection in your household once doesn’t necessarily mean it won’t happen again. Children can get croup more than once.
Can Adults Get Croup from Children?
Croup can be passed among children and from a child to an adult. However, adults are much less likely to develop symptoms because they have larger airways—swelling doesn’t affect them as much.
Adults often get croup from being in close contact with children who are contagious with the croup infection. In rare cases, croup is linked to allergies, bacteria, or acid reflux from the stomach.
Symptoms of croup include:
Croup typically gets worse before it improves: The illness begins with cold-like symptoms and progresses to the barking-cough characteristic of croup and breathing difficulties.
In the most serious cases (which are rare), experts say signs of croup worsening to emergency status include a pale or bluish color around the mouth due to a lack of oxygen.Less than 5% of children with croup require hospitalization.Even in these cases, hospitalization for croup is typically no more than a few hours to two days.
What’s the Difference Between Croup, RSV, and Whooping Cough?
Respiratory syncytial virus (RSV)refers to both a common respiratory illness and one of the viruses that can cause croup. Symptoms of the illness are typically mild and similar to those of the flu or COVID-19, including:
People with RSV are contagious for longer than those with croup: for three to eight days in most cases and for up to four weeks if they’re infants or haveweakened immune systems.
Whooping cough, also known as pertussis, leads to a distinctive “whoop” sound when a person inhales after a coughing fit. It starts with mild symptoms similar to RSV and progresses to severe coughing fits that usually last between one and six weeks. Whooping cough vaccines are available to help prevent the disease or make its course milder.
When to Seek Immediate Medical Care
Complications with croup are uncommon. Experts recommend calling 911 or going directly to the nearest emergency room if the child with a croup infection experiences the following symptoms:
How to Prevent Spread
To prevent the spread of croup, children with symptoms should not go to school or daycare for the first three days after the onset of symptoms—or until their fever resolves.
Other methods of preventing the spread of croup to others include:
Summary
Croup is an infection typically seen in children between the ages of 3 months and 5 years. The virus can spread among children and between children and adults. However, older children and adults typically don’t experience any symptoms.
The croup infection is contagious until three days after symptoms start or, if fever is present, until the fever resolves. While a person with croup is contagious, the virus in mucus or respiratory droplets spreads through sneezing, coughing, crying, and wheezing.
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Cedars-Sinai.Croup in children.Nationwide Children’s Hospital.Croup.MedlinePlus.Croup.Texas Children’s Hospital.Common illnesses seen after natural disasters: Croup.Woods, Charles.Patient education: Croup in infants and children (beyond the basics).American Academy of Family Physicians’ Family Doctor.Croup.Nemours Kids Health.Croup.Smith DK, McDermott AJ, Sullivan JF.Croup: diagnosis and management.Am Fam Physician. 2018;97(9):575-580.Johns Hopkins Medicine.Croup.Seattle Children’s Hospital Research Foundation.Croup.National Foundation for Infectious Diseases.Respiratory syncytial virus (RSV).Centers for Disease Control and Prevention.Symptoms of whooping cough.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Cedars-Sinai.Croup in children.Nationwide Children’s Hospital.Croup.MedlinePlus.Croup.Texas Children’s Hospital.Common illnesses seen after natural disasters: Croup.Woods, Charles.Patient education: Croup in infants and children (beyond the basics).American Academy of Family Physicians’ Family Doctor.Croup.Nemours Kids Health.Croup.Smith DK, McDermott AJ, Sullivan JF.Croup: diagnosis and management.Am Fam Physician. 2018;97(9):575-580.Johns Hopkins Medicine.Croup.Seattle Children’s Hospital Research Foundation.Croup.National Foundation for Infectious Diseases.Respiratory syncytial virus (RSV).Centers for Disease Control and Prevention.Symptoms of whooping cough.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Cedars-Sinai.Croup in children.Nationwide Children’s Hospital.Croup.MedlinePlus.Croup.Texas Children’s Hospital.Common illnesses seen after natural disasters: Croup.Woods, Charles.Patient education: Croup in infants and children (beyond the basics).American Academy of Family Physicians’ Family Doctor.Croup.Nemours Kids Health.Croup.Smith DK, McDermott AJ, Sullivan JF.Croup: diagnosis and management.Am Fam Physician. 2018;97(9):575-580.Johns Hopkins Medicine.Croup.Seattle Children’s Hospital Research Foundation.Croup.National Foundation for Infectious Diseases.Respiratory syncytial virus (RSV).Centers for Disease Control and Prevention.Symptoms of whooping cough.
Cedars-Sinai.Croup in children.
Nationwide Children’s Hospital.Croup.
MedlinePlus.Croup.
Texas Children’s Hospital.Common illnesses seen after natural disasters: Croup.
Woods, Charles.Patient education: Croup in infants and children (beyond the basics).
American Academy of Family Physicians’ Family Doctor.Croup.
Nemours Kids Health.Croup.
Smith DK, McDermott AJ, Sullivan JF.Croup: diagnosis and management.Am Fam Physician. 2018;97(9):575-580.
Johns Hopkins Medicine.Croup.
Seattle Children’s Hospital Research Foundation.Croup.
National Foundation for Infectious Diseases.Respiratory syncytial virus (RSV).
Centers for Disease Control and Prevention.Symptoms of whooping cough.
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