Medications used for co-morbidities
Thirty-six patients (14.4%) used methylphenidate (or other comparable drugs) as a chronic medication for attention deficit disorder with or without hyperactivity. Although not statistical significantly, the percentage of patients who used methylphenidate increased parallel to the duration of CSU (11% of patients with CSU <12 months, 15.6% of patients with CSU for 12-24 months and 20% of patients with CSU > 24 months).