Raynaud’s phenomenon is a vasospastic disorder with a reported prevalence of between 3% and 5% of the general population, is nine times more common in females and typically occurs between the ages of 15–40 years. It may be primary or occur in the setting of connective tissue disorders. Exaggerated vasoconstriction of the digital arteries in response to certain environmental triggers, typically cold temperatures, leads to pale, cold, numb and sometimes painful digits. In extreme cases, digital artery vasospasm leads to diminished blood supply to the fingertips, which causes pain, disuse and exposure of the distal phalanx, and may necessitate amputation.

Injection of botulinum neurotoxin (BoNT) into the hand, typically at the base of the fingers, produces increased blood flow, oxygenation saturation, pain reduction and promotion of ulcer healing, with prolonged benefit over several months. This chapter details the use of BoNT for ischemic digits caused by Raynaud’s phenomenon, including injection technique, dosing and quantification of perfusion and oxygenation using laser Doppler.