Is there a distinct pathogenetic mechanism of headache in SLE?
(iv) Is headache related to CNS involvement or general SLE activity? (v) Is headache related to anxiety- and depression-like symptoms in SLE? All published articles reporting data from >30 SLE patients were classified into four classes (I, IIa, IIb and III) by the quality of their evidence. We found no prospective controlled study (class I), but we identified seven controlled (class II) and 28 uncontrolled studies (class III) that retrospectively investigated the occurrence of headache in SLE patients. Eight out of 35 studies applied the International Headache Society (IHS) criteria for headache classification, whereas only four uncontrolled studies investigated paediatric SLE populations (class III). Pooled data from eight studies (controlled and uncontrolled) that used the IHS criteria show that 57.1% of SLE patients reported any type of headache (migraine 31.7% and tension-type headache 23.5%). Pooled data from seven controlled studies showed that the prevalence of all headache type