Erythema Toxicum Neonatorum - Diagnosis

Diagnosis

At times the appearance can raise concern that the rash could be due to herpes simplex; however, the latter generally has a more clustered and vesicular appearance.

In uncertain cases, a scraping of a lesion can be done and the fluid examined under the microscope. Herpes lesions will have a positive direct fluorescent antibody test. The fluid from erythema toxicum lesions will show many eosinophils.