CBC
leukocytosis with neutrophilia
anemia (more common in malignancy or drug associated)
platelet abnormalities (more common in malignancy or drug associated)
Complete metabolic panel
Urinalysis
ESR
CRP
leukocytosis with neutrophilia
anemia (more common in malignancy or drug associated)
platelet abnormalities (more common in malignancy or drug associated)
Abrupt onset painful erythematous plaques or nodules
Histopathological evidence of neutrophilic infiltrate without evidence of leukocyoclastic vasculitis
Fever
Associated malignancy, IBD, pregnancy, preceding URI, preceding GI infection
Improvement with treatment with systemic steroids
Abnormal labs (3+ of following): ESR > 20, elevated CRP, leukocytosis, neutrophilic predominance
Sweet's syndrome
Infectious
Staphylococcal scalded skin syndrome
Adenovirus
Rabies
Arbovirus
Drug rash
EBV