Croup is contagious and transferred from someone who is infected. The transfer of croup may occur from the hand or from tiny air droplets. The croup can last between three to seven days, and the worst at night time.
Adults are rarely infected with croup. However, if your child has viral croup, you may catch a cold.
There are two types of croup: viral and spasmodic. The most common type of croup is viral. The windpipe and voice box are infected with the viral croup.
Spasmodic croup is caused by allergies or reflux from the stomach. Spasmodic comes on very suddenly. You will not have a fever with spasmodic croup. Spasmodic croup may recur frequently.
According to the NIH and AAP websites, croup symptoms include:
• Mild cold symptoms
• Hoarse voice
• Low grade fever
• The Croup Cough
• Labored breathing
• Stridor (a harsh, crowing noise made during inspiration)
https://www.empowher.com/croup/content/croup-symptoms-and-treatment