Systemic inflammatory biomarkers in painful diabetic neuropathy

•Inflammation seems to be the common denominator of nerve damage and pain in diabetic peripheral neuropathy.•TNF-α characterizes pain not only in painful diabetic peripheral neuropathy but also in neuropathies of different origins.•Growth factors are associated with the genesis of peripheral neuropathy in patients with DM but not with the genesis of pain.•An entire inflammatory network appears to be responsible for pain in diabetic peripheral neuropathy.