Pain in primary Sjogren's syndrome.

Joint and muscle pain are commonly observed in patients with primary Sjogren's syndrome (pSS). Different types of pain can be distinguished, that is, articular pain, neuropathic pain and widespread pain. Articular pain is due to more or less evident synovitis, usually involving peripheral joints such as hand joints, wrists, knees and ankles. Drugs used to treat rheumatoid arthritis, or lupus synovitis, are also employed for articular involvement in pSS. Pure sensory neuropathies and, more often, small fibre neuropathies are responsible for neuropathic pain in pSS. This is usually localised in the legs and arms with a characteristic glove or sock distribution. Widespread pain, often assuming the features of fibromyalgia, has also been reported in patients with pSS. The pathological mechanisms underlying both neuropathic pain and widespread (fibromyalgia) pain in pSS have not been so far completely clarified.