According to Harvard Health Publishing, viral croup is more common during the fall and winter months. It is typically caused by a viral infection such as the parainfluenza virus and usually occurs in children between 6 months and 3 years old, says the Mayo Clinic. Viral croup symptoms can range from mild to severe. Besides the barking cough, other symptoms may include fever, sore throat, and noisy breathing, and the condition can last 3 to 5 days.
Spasmodic croup, on the other hand, is not caused by an infection but rather by an allergic reaction and affects children younger than 6 years old, according to Harvard Medical School. The symptoms of spasmodic croup are similar to those of viral croup, including a barking cough. However, the onset of symptoms in spasmodic croup is often sudden and may worsen in the middle of the night, improve during the day, and reoccur again overnight for several days. Immediate medical attention will be needed if the symptoms are caused by a food allergy, warns WebMD.