Hypothermia or Cold Injury: Given the context of dumpster diving, which may involve exposure to cold environments, especially if the individual was in a cold dumpster or outside in cold weather for an extended period, hypothermia or cold injury (such as frostbite) could lead to discolored and numb toes.

Trauma: Direct trauma to the toes from the dumpster diving activity could cause discoloration (bruising) and numbness due to nerve injury or compression.
Infection: Exposure to unsanitary conditions during dumpster diving increases the risk of infections, which could lead to symptoms like discoloration and numbness if the infection affects the toes.
Toxic Exposure: Exposure to toxic substances while dumpster diving could potentially cause neurological symptoms like numbness, though this might be less common.

Gas Gangrene: Although rare, gas gangrene (clostridial myonecrosis) is a potentially deadly condition that could result from a traumatic wound becoming infected, especially in the context of unsanitary conditions. Early recognition is crucial.
Tetanus: Another infection that could result from wounds sustained during dumpster diving, tetanus can lead to severe neurological symptoms, including numbness, though it typically presents with muscle stiffness and spasms.
Sepsis: If an infection is present, there's a risk of it becoming systemic (sepsis), which is life-threatening and requires immediate medical attention.

Raynaud's Phenomenon: A condition that affects blood flow to the fingers and toes, and can be triggered by cold or stress, leading to discoloration and numbness. It's less likely given the acute onset in this context but could be considered if other causes are ruled out.
Erythromelalgia: A rare disorder characterized by burning pain, heat, and redness in the hands and feet, which could potentially be triggered by certain exposures or conditions. However, numbness is not a typical primary symptom.