Boston—During the 2 years of the pandemic, advice on which symptoms suggest COVID-19 has changed constantly. A new manifestation might be of special interest to pharmacists who are often asked by parents when testing is necessary for their children.

Especially during the Omicron variant surge, Boston Children's Hospital clinicians have determined that croup is a previously unrecognized complication of COVID-19 in young children.

A prepublication article in the journal Pediatrics describes cases in 75 children who came to the hospital's emergency department (ED) with croup and COVID-19 from March 1, 2020, through January 15, 2022.

The authors recounted how some cases were severe and required hospital admissions and more medication doses compared with croup caused by other viruses. Most occurred during the recent Omicron period.

"There was a very clear delineation from when omicron became the dominant variant to when we started seeing a rise in the number of croup patients," explained first author Ryan Brewster, MD, a first-year resident in the Boston Combined Residency Program in Pediatrics at Boston Children's Hospital and Boston Medical Center.

Laryngotracheitis, commonly called croup, is a common respiratory illness in babies and young children and involves a distinctive barking cough and sometimes stridor, which is a noisy, high-pitched intake of breath. It occurs when colds and other viral infections cause inflammation and swelling around the voice box, windpipe, and bronchial tubes. Severe cases, including some seen at Boston Children's, can dangerously constrict breathing.

The researchers pointed out that studies of COVID-19 in animals have found that the Omicron strain has more of a "preference" for the upper airway than earlier variants, which often targeted the lower respiratory tract. Dr. Brewster suggested that might explain the upsurge in croup.

"Endemic coronaviruses have been linked to croup; however, only sparse case reports have described croup specifically associated with SARS-CoV-2 and it remains unclear if croup cases constitute a causative relationship or result of co-infection with another virus," the study explained. "To address this knowledge gap, we performed a retrospective analysis of the incidence and clinical characteristics of croup associated with SARS-CoV-2 infection at a large freestanding children's hospital."

Results indicated that—as is typical with croup—most of the children who had the condition with COVID-19 were aged younger than 2 years, and 72% percent were boys. One child had a common cold virus, but none of the others had a viral infection other than SARS-CoV-2.

None of the children died, but 12% of the 75 children with COVID-19-associated croup required hospitalization, with 5% of the total needing intensive care. That is much higher than in typical croup cases, where fewer than 5% ended up in the hospital, the study noted.

The authors advised that nearly all (97%) of the children were treated with dexamethasone. About 29% of children seen in the ED, as well as all of the inpatients, additionally received racemic epinephrine via nebulizer, which is reserved for moderate or severe cases. The hospitalized children required a median of six doses of dexamethasone and eight nebulized epinephrine treatments to control their symptoms.

"Most cases of croup can be managed in the outpatient setting with dexamethasone and supportive care," stated Dr. Brewster. "The relatively high hospitalization rate and the large number of medication doses our COVID-19 croup patients required suggests that COVID-19 might cause more severe croup compared to other viruses. Further research is needed to determine the best treatment options for these children."

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