Should include the following 
CBC with differential
Chem (if starting acyclovir)
LFTs
Whole blood<unk>  PCR
Blood, urine culture, urinalysis
LP with CSF studies including<unk>  PCR
Perform PCR/culture of:
Any visible lesions
Conjunctiva, nasopharynx, mouth, anus
Even in the absence of lesions
Consider CXR for respiratory symptoms
Suspected CNS disease should undergo EEG, with discussion of imaging with infectious disease and neurology consultants (does not need to be completed in the ED unless there is an abnormal neuro exam)
Suspected ocular involvement should get optho consult
CBC with differential
Chem (if starting acyclovir)
LFTs
Whole blood<unk>  PCR
Blood, urine culture, urinalysis
LP with CSF studies including<unk>  PCR
Perform PCR/culture of:
Any visible lesions
Conjunctiva, nasopharynx, mouth, anus
Even in the absence of lesions
Consider CXR for respiratory symptoms
Suspected CNS disease should undergo EEG, with discussion of imaging with infectious disease and neurology consultants (does not need to be completed in the ED unless there is an abnormal neuro exam)
Suspected ocular involvement should get optho consult
Any visible lesions
Conjunctiva, nasopharynx, mouth, anus
Even in the absence of lesions
Even in the absence of lesions
Always consider<unk>  and perform appropriate work-up and treatment if:
Evidence of vesicular rash (even if minor)
Keratoconjunctivitis
Seizure
Poor feeding
Lethargy
Irritability
Respiratory distress
Sepsis
Temperature instability
CSF pleocytosis
Thrombocytopenia
Transaminitis
Working up for serious bacterial illness
Evidence of vesicular rash (even if minor)
Keratoconjunctivitis
Seizure
Poor feeding
Lethargy
Irritability
Respiratory distress
Sepsis
Temperature instability
CSF pleocytosis
Thrombocytopenia
Transaminitis
Working up for serious bacterial illness
Neonatal HSV
Upper respiratory infection 
Rubella
UTI
Smallpox
Sepsis
Syphilis
Meningitis