Health professionals can diagnose<unk>  with a skin exam. Most cases of<unk>  can be diagnosed without further testing. If more testing is needed to make a diagnosis, the contents of a lesion can be examined under a microscope. A health professional may make a small cut into a pus-filled lesion and collect a swab of pus for testing. Lesions caused by<unk>  contain eosinophils and other immune cells. These cells can be seen under a microscope when a special stain is applied to the sample. Since the appearance of<unk>  varies, it may be confused with other newborn rashes. Some newborn infections cause bumps or boils, which may look like<unk> . Bacterial infections, including Staphylococcus and Streptococcus infections, almost always cause additional symptoms. These symptoms may be severe, and they are usually not limited to rash. Bacterial rashes can be diagnosed by testing pus from a lesion along with a blood sample. Bacteria can be seen under a microscope with a special stain or may be found on a culture. Fungal infection with Candida may also cause a similar rash in newborns, but it usually causes additional symptoms like thrush. Similarly, fungus can be seen under a microscope or found on a culture. Some viral infections may cause a rash with boils on a reddish base. Rashes caused by herpes simplex virus and varicella zoster virus in particular may be confused with<unk> . These viruses are diagnosed by scraping the base of a lesion. Multinucleated giant cells can be seen under a microscope. Some of these tests may be ordered if the diagnosis is unclear.
Erythema toxicum neonatorum
Papular eruption of blacks
Bradyphrenia
Prurigo gestationis
Erythema dyschromicum perstans
Noma neonatorum
Arbor vitae 
Cutis marmorata telangiectatica congenita