• Medical Author:
    John Mersch, MD, FAAP

    Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Quick GuideChildhood Illnesses: A Parenting Guide to Sick Kids

Childhood Illnesses: A Parenting Guide to Sick Kids

How is the diagnosis of croup established?

The diagnosis of croup is most commonly made by obtaining the characteristic history of sudden-onset of hoarse voice, barky cough, stridor during inhalation, and the possibility of low-grade fever. While the child may appear rather ill, the child does not have a look of pure panic or terror. There can be high fever (> 103 F), sitting forward positioning, and excessive drooling. A recent exposure to another child with croup helps to confirm the diagnosis. Laboratory tests are rarely necessary and are mostly limited to severe situations where concern regarding a secondary bacterial infection may have developed and is superimposed upon the primary viral process. A particular X-ray orientation of the neck will often show a characteristic elongated narrowing of the region called a "steeple sign." Such an X-ray finding is confirmatory for croup. Rarely will consultation with an otolaryngologist (ENT physician) be necessary to have a direct visual examination of the patient's airway. Such a procedure is termed fiberoptic laryngoscopy and is indicated if there is a concern for an anatomical malformation of the upper airway, possible aspiration of a foreign object, or should the child rapidly deteriorate or not respond to routine therapy in the anticipated manner.

Most infants are routinely immunized against the bacteria Haemophilus influenzae type B (Hib). When the child is not immunized against Hib, the possibility of a more ominous, deep bacterial infection called epiglottitis exists. Continue Reading

Reviewed on 12/14/2015

Malhotra, A., and L.R. Krilor. "Viral Croup." Pediatrics in Review 22.1 Jan. 2001: 5-12.

United States. Centers for Disease Control and Prevention. "Human Parainfluenza Viruses (HPIVs)." Aug. 18, 2015. <>.

Woods, Charles R. "Patient Information: Croup in Infants and Children." Aug. 18, 2010. <>. IMAGES:

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4. MedicineNet

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9. BigStock

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