Chronic kidney disease (uremia)
Vitamin deficiency (vitamin B12 and occasionally vitamin B6)
Alcohol abuse
Low thyroid hormone levels (hypothyroidism)
Lyme disease
HIV/AIDS
Amyloid polyneuropathy
Drug side effects, including chemotherapy drugs, vitamin B6
overdose, HIV medicines, isoniazid, amiodarone, metformin, and others
Heavy metal poisoning (lead, mercury, arsenic)
Vasculitis (inflammation of blood vessels)
Sarcoidosis
Guillain-Barre syndrome
Arterial disease
Edema or fluid retention
Hyp