Peripheral Artery Disease (PAD): This condition is characterized by the narrowing or blockage of the blood vessels outside of the heart, leading to reduced blood flow to the limbs. Bluish discoloration of the toes (cyanosis) can occur due to inadequate oxygen delivery.

Raynaud's Phenomenon: A condition that affects blood flow to the fingers and toes, and sometimes the ears, nose, and lips. It is marked by a sudden and temporary narrowing of the arteries in response to cold temperatures or stress, causing the affected areas to turn blue.
Diabetes Mellitus with Peripheral Neuropathy and Vascular Disease: Diabetes can lead to both nerve damage (neuropathy) and vascular disease, which can impair blood flow to the toes, potentially causing bluish discoloration.
Smoking-Related Vascular Disease: Smoking is a significant risk factor for vascular diseases, including PAD and other conditions that can lead to reduced blood flow to the extremities, resulting in cyanosis.

Acute Limb Ischemia: A sudden decrease in limb perfusion that threatens limb viability, requiring immediate medical attention. It can cause severe pain, pallor, pulselessness, poikilothermia, paresthesias, and paralysis, and if not promptly treated, can lead to gangrene and amputation.
Deep Vein Thrombosis (DVT): A blood clot that forms in a vein deep inside your body, typically in your leg. It can cause swelling, redness, and bluish discoloration due to obstruction of blood flow.
Aortic Dissection: A serious medical condition where there is a tear in the inner layer of the aorta, which can lead to a blockage of blood flow to various parts of the body, including the lower limbs, potentially causing bluish toes.

Buerger's Disease (Thromboangiitis Obliterans): A rare disease of the arteries and veins in the arms and legs, leading to blockages that can result in pain, tissue damage, and potentially cyanosis.
Erythromelalgia: A disorder characterized by burning pain, heat, and redness in the hands and feet, which can sometimes present with cyanosis due to abnormal blood flow.
Chronic Hypoxia due to Respiratory or Cardiac Conditions: Conditions such as chronic obstructive pulmonary disease (COPD) or heart failure can lead to chronic hypoxia, which might cause cyanosis in the toes, although this is less common compared to other presentations of cyanosis.