Procalcitonin as a diagnostic indicator for systemic bacterial infections in patients with Stevens–Johnson syndrome/toxic epidermal necrolysis

Elevated serum procalcitonin (PCT) level has been reported to be a diagnostic index in systemic bacterial infections, but it can also increase in some non‐infectious inflammatory diseases. Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) is a rare immune‐mediated cutaneous mucosal reaction which is susceptible to bacterial infections and may have elevated PCT levels. The value of serum PCT has not been assessed in series of SJS/TEN patients. We aimed to investigate the PCT levels in SJS/TEN patients with systemic bacterial infections (systemic infected group), with skin surface bacterial infections (skin surface infected group) and without infections (non‐infected group), to assess whether PCT was a valuable indicator for systemic bacterial infections in SJS/TEN patients. The PCT and C‐reactive protein (CRP) levels of 42 inpatients with SJS/TEN were retrospectively analysis. The receiver–operator curve (ROC) was used to determine the diagnostic efficacy of PCT for systemic bacterial infections in SJS/TEN patients. The results demonstrated that PCT levels in the systemic infected group were significantly higher than those in the other two groups (P < 0.05). There was no significant difference in CRP between the three groups. The cut‐off PCT level of 0.65 ng/mL calculated by ROC had optimal diagnostic efficacy, with sensitivity and specificity of 84.6% and 89.7%, respectively. PCT and severity‐of‐illness score for toxic epidermal necrolysis were positively correlated (P < 0.05). In conclusion, PCT is a valuable index and superior to CRP in detecting systemic bacterial infections in SJS/TEN patients. The level of PCT can partially reflect the severity of the disease.