Neonatal Urticaria as the First Manifestation of Neonatal Onset Multisystem Inflammatory Disease Treated Empirically With Anakinra.

Urticarial eruptions in neonates, especially within hours to days of birth, should prompt workup for cryopyrin-associated periodic syndrome (CAPS) disorders. This report details a 9-h-old neonate with urticaria as the first manifestation of neonatal onset multisystem inflammatory disease (NOMID), also known as chronic infantile neurologic cutaneous and articular syndrome. Empiric anakinra was started on Day 3 of life, prior to genetic confirmation of a de novo pathogenic variant of NLRP3, due to high clinical suspicion for CAPS and in the absence of an infectious source. As early treatment reduces morbidity and mortality, this case highlights the importance of having a low threshold for empiric anti-IL-1 therapy in neonatal urticaria with clinical suspicion for NOMID.