Urticaria Neonatorum: accumulation of tryptase-expressing mast cells in the skin lesions of newborns with Erythema Toxicum

Benign skin disease with pustules in the newborn

The neonatal period comprises the first four weeks of life. It is a period of adaptation where the skin often presents several changes: transient lesions, resulting from a physiological response, others as a consequence of transient diseases and some as markers of severe disorders. The presence of pustules in the skin of the newborn is always a reason for the family and for the assisting doctor to be worried, since the newborn is especially vulnerable to bacterial, viral or fungal infection. However, the majority of neonatal skin pustules is not infectious, comprising the benign neonatal pustulosis. Benign neonatal pustuloses are a group of clinical disease characterized by pustular eruptions in which a contagious agent is not responsible for its etiology. The most common ones are erythema toxicum neonatorum, the transient neonatal pustular melanosis and the benign cephalic pustulosis. These dermatoses are usually benign, asymptomatic and self-limited. It is important that the dermatologist and the neonatologist can identify benign and transient lesions, those caused by genodermatoses, and especially differentiate between neonates with systemic involvement from those with benign skin lesions, avoiding unnecessary diagnostic tests and worries.

Eosinophilic Endomyocarditis: A Rare Case of Neonatal Mortality

Background Eosinophilic endomyocarditis (EEM) is a rare diagnosis that is extremely uncommon in newborns. This case report aimed to present a case of neonatal mortality from acute cardiac failure due to EEM. Case Our report presents a term male neonate with minor complications in the immediate postnatal course, who was discharged at 48 hours of life, but who developed unexpected respiratory distress, followed by cardiac arrest and death at 3 days of life. One day after discharge, the infant developed respiratory distress and cool skin, and then developed cardiac arrest at the pediatrician's office, undergoing resuscitation with intravenous fluid, cardiopulmonary resuscitation, epinephrine, atropine, and failed intubation. Autopsy revealed EEM, an inflammatory infiltrative process involving the endomyocardium. Pathology Pathogenesis involves three stages: (1) myocarditis with an acute eosinophilic inflammatory infiltrate followed by (2) myocyte necrosis and eventually (3) fibrosis in the final stage of the disease. Discussion The cause of death was acute cardiac failure due to intense eosinophilic infiltration and degranulation with early subendocardial myocyte necrosis but before development of extensive myocyte necrosis. This case appears to be the youngest patient reported with EEM.

Total serum tryptase levels are higher in young infants

BACKGROUND

Mast cells participate in immune defense and allergic disease. At baseline, serum tryptase levels primarily reflect mast cell burden, while mast cell degranulation leads to granule tryptase release, which may be detectable as a transitory elevation of serum tryptase levels. Thus, mast cell burden and mast cell activity are reflected by serum tryptase levels, but reports are scarce in infants under 1 yr. We aimed at defining levels of total serum tryptase levels in this population.

METHODS

Total serum tryptase levels (ImmunoCAP; Phadia) were measured in 372 sera from infants younger than 1 yr. Two hundred and forty-two sera came from non-atopic, non-allergic infants in good condition, who had blood drawn for routine follow-up or diagnosis of illnesses that are not known to induce changes in serum tryptase levels. Seventy-two sera were from atopic and/or allergic infants, and 58 sera were from non-atopic, non-allergic infants requiring intensive care.

RESULTS

Median serum tryptase levels were highest in infant2s under 3 months (6.12 ± 3.47 μg/l) and gradually decreased before reaching levels similar to those described in adults and older children (3.85 ± 1.8 μg/l between 9 and 12 months). Atopic/allergic status was associated with even higher tryptase levels (14.20 ± 10.22 μg/l in infants younger than 3 months). Intensive care patients had lower levels of serum tryptase (4.12 ± 3.38 μg/l in infants younger than 3 months). Longitudinal follow-up was performed in 27 patients and showed tryptase levels decrease over time in individual patients. Infants'sex was not found to interfere with serum tryptase levels.

CONCLUSION

Total serum tryptase levels are significantly higher in younger infants compared with older ones. In infants of the same age, serum tryptase levels may vary according to the clinical condition and thus suggest mast cell involvement in the physiologic as well as in the allergic immune responses of young infants.

Role of innate host defenses in susceptibility to early-onset neonatal sepsis

Neonatal sepsis continues to take a devastating toll globally. Although adequate to protect against invasive infection in most newborns, the distinct function of neonatal innate host defense coupled with impairments in adaptive immune responses increases the likelihood of acquiring infection early in life, with subsequent rapid dissemination and death. Unique differences exist between neonates and older populations with respect to the capacity, quantity, and quality of innate host responses to pathogens. Recent characterization of the age-dependent maturation of neonatal innate immune function has identified novel translational approaches that may lead to improved diagnostic, prophylactic, and therapeutic modalities.