What cellular component is typically found in erythema toxicum?

Erythema toxicum is a common, benign cutaneous condition observed in newborns, characterized by transient, erythematous macules and papules that can often resemble insect bites. The hallmark of this condition is the presence of eosinophils in the lesions. Eosinophils are a type of white blood cell involved in allergic reactions and combating parasitic infections, and they play a significant role in the inflammatory responses seen in various dermatological conditions.

In the context of erythema toxicum, the presence of eosinophils indicates that the skin is undergoing a reactive process, often associated with the normal adaptation of the newborn to extrauterine life. This is not typically related to infections or severe inflammatory responses, which would be indicated by other cell types such as neutrophils. Understanding the role of eosinophils in this situation provides insight into the harmless nature of erythema toxicum, as it usually resolves spontaneously without any treatment, signifying normal immunological development in neonates.