The diagnosis of<unk>  is made clinically based on the presence of the two phases: fever and rash. Laboratory testing is seldom used as the results do not alter management of the disease. An exception is in people who are immunocompromised in who serologic tests with viral identification can be used to confirm the diagnosis.<unk>  should be differentiated from other similar-appearing illnesses, such as rubella, measles, fifth disease, scarlet fever, and drug reactions. This differentiation may be determined based on symptoms.
Roseola
Rubella
Ebola
Scarlet fever
Measles
Mumps
Smallpox
Chickenpox