Trauma: This is often the most common reason for toe discoloration, as injuries can cause bruising, leading to changes in skin color. The history of a recent injury makes this a likely diagnosis.

Poor Circulation: Conditions that affect blood flow to the toes, such as peripheral artery disease (PAD), can lead to discoloration due to inadequate oxygen delivery.
Frostbite: Exposure to cold temperatures can cause damage to the skin and underlying tissues, resulting in discoloration.
Infection: Bacterial or fungal infections, such as cellulitis or athlete's foot, can cause redness, swelling, and discoloration of the toes.
Erythromelalgia: A condition characterized by burning pain, heat, and redness in the hands and feet, which can also cause discoloration.

Gangrene: A serious condition that occurs when tissue dies due to a lack of blood supply. It is crucial to identify and treat promptly to prevent further tissue loss and potential amputation.
Deep Vein Thrombosis (DVT): A blood clot in the deep veins, which can cause discoloration, swelling, and warmth in the affected limb. DVT can lead to pulmonary embolism if the clot breaks loose.
Sepsis: A life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Sepsis can cause discoloration, among other symptoms, and requires immediate medical attention.

Argyria: A rare condition caused by exposure to silver or silver compounds, leading to a blue-gray discoloration of the skin and mucous membranes.
Chilblains: A condition that occurs in response to cold temperatures, causing damage to small blood vessels and resulting in discoloration, itching, and pain.
Methemoglobinemia: A disorder characterized by an abnormal amount of methemoglobin, a form of hemoglobin, in the blood. This can cause cyanosis, a bluish discoloration of the skin and mucous membranes.
Buerger's Disease: A rare disease of the arteries and veins in the arms and legs, which can cause discoloration, pain, and ulcers due to reduced blood flow.