TOPLINE:
Among infants, most cases of urticaria of unknown etiology are acute urticaria (AU) and self-resolve, even when the cause is not identified.
METHODOLOGY:
- Literature on the disease course of urticaria in infants is sparse.
- To characterize the clinical course of urticaria of unknown etiology, researchers retrospectively evaluated the charts of 246 infants younger than 12 months who were seen for the condition at Boston Children's Hospital between January 2016 and January 2021.
- They classified urticarial episodes lasting less than 6 weeks as AU, recurrent urticarial lesions occurring more than twice weekly for at least 6 consecutive weeks as chronic urticaria (CU), and elucidated etiology at follow-up visits either through further clinical history or testing.
- Time to resolution of urticaria was based on date of the earliest clinical note documenting disease resolution unless it was otherwise specified in clinical notes.
TAKEAWAY:
- The mean age of the infants at their first visit for urticaria was 7 months; 39% were female; 58.9% were White, 5.3% were Asian, 2.4% were Black, and 5.3% were Hispanic/Latinx; and 88% had AU.
- A total of 131 infants were seen for a follow-up: 115 with AU and 16 with CU. The researchers eventually identified the etiology in 62.6% of the AU cases and 12.5% of the CU cases.
- Among the AU cases, the two most common etiologies were food allergy (44.3%) and infection (13.0%), but the etiology remained unknown in 37.4% cases. Among the CU cases, the etiology was identified as an infection in one case (6.3%), and annular erythema of infancy in one case (6.3%) but remained unidentified in the 14 other cases (87.5%).
- In other findings, 50% of the CU cases resolved in a median of 15.5 months.
IN PRACTICE:
"Pediatric healthcare providers can reassure families that the majority of cases of infant urticaria of unknown etiology self-resolve and that further workup is not necessary in the absence of other signs or symptoms," the researchers wrote.
SOURCE:
Jennifer T. Huang, MD, a dermatologist at Harvard Medical School and Boston Children's Hospital, led the research. The study was published online on January 9, 2024, in Pediatric Dermatology.
LIMITATIONS:
The single-center retrospective design, small sample size, and limited follow-up data.
DISCLOSURES:
The authors reported having no relevant conflicts of interest.