C-reactive protein is linked to disease activity, impact, and response to treatment in patients with chronic...

Elevated levels of C-reactive protein (CRP), a sensitive marker of inflammation, have been consistently reported in chronic spontaneous urticaria (CSU). Here, we retrospectively analyzed data from 1253 CSU patients from 2 centers to answer the following questions: (i) What is the prevalence of elevated levels of CRP in CSU? (ii) Why do CSU patients show elevated levels of CRP? (iii) Are elevated CRP levels relevant?

Serum levels of CRP were measured by the nephelometric method. We collected information regarding various laboratory tests including ESR, CBC with differential, D-dimer, fibrinogen, C3, C4, IL-6, etc. For most patients, we also collected data on age, gender, duration of CSU, presence of angioedema, activity (UAS at the time of blood sampling and for 7 days), quality of life (CU-Q2oL and/or DLQI), comorbidities and possible causes of CSU, and autologous serum skin test (ASST) response. The efficacy of second-generation antihistamines was evaluated on the day of blood collecting.

One-third of CSU patients had elevated levels of CRP. Higher levels of CRP were associated with ASST positivity (P = .009) and arterial hypertension (P = .005), but not with other possible causes or comorbidities of CSU. C-reactive protein correlated with urticaria activity (P < .001), quality of life impairment (P = .026), and inflammatory and coagulation markers (P < .001). C-reactive protein levels were significantly higher in nonresponders to antihistamines as compared to responders (P < .001).

Elevated levels of CRP are common and relevant in CSU patients. The assessment of CRP levels may help to optimize the management of patients with CSU.