Table 5.

Differentiating infection from inflammation (flare) in SLE patients

Features suggestive of infection	Features suggestive of inflammation (flare)	Features which may be common to both
Raised CRP	Normal CRP (may be raised in pericarditis, pneumonitis, or arthritis)	Symptoms (nausea, vomiting, pleuritic pain, arthralgia)
Raised WCC	Response to immunosuppression	Fever
Response to antibiotics	Low complement (C3 and C4)	Reduced WCC
Raised procalcitonin (intensive care setting)	Raised dsDNA antibodies

Note: Data from Ateka-Burrutia et al,⁸ and Beca et al.⁵²

Abbreviations: SLE, systemic lupus erythematosus; CRP, C-reactive protein; WCC, white cell count.