Purple hands may be symptomatic of a number of medical conditions, including peripheral neuropathy, carpal tunnel syndrome, Raynaud's phenomenon, generalized anxiety disorder or vitamin B12 deficiency. Purple hands may also be due to exposure to cold, but numbness or a feeling of cold is typical of most conditions associated with this symptom.
According to the NHS, Raynaud's phenomenon is a condition caused by a spasm of blood vessels, blocking the flow of blood to the hands. It may be related to cold exposure or anxiety.
The condition is not a serious problem and may be treated by protecting the hands against cold or else practicing relaxation exercises.