Peripheral neuropathy: This is a common condition that can cause numbness in the toes due to damage to the peripheral nerves. It can be caused by various factors such as diabetes, vitamin deficiencies, or trauma. Given the age and presentation of the patient, this is a plausible diagnosis.

Tarsal tunnel syndrome: This condition is caused by compression of the posterior tibial nerve as it travels through the tarsal tunnel on the inner side of the ankle. It can cause numbness, tingling, and pain in the toes.
Morton's neuroma: This is a condition where a nerve in the foot becomes irritated or compressed, causing numbness, tingling, and pain in the toes.
Radicular pain: This can occur if there is compression or irritation of the nerve roots in the lower back, which can cause numbness or pain in the toes.

Diabetic neuropathy: Although the patient is young, it's essential to consider diabetes as a potential cause, especially if there are other symptoms such as weight loss or polyuria.
Multiple sclerosis: This is an autoimmune disease that can cause numbness, tingling, and weakness in various parts of the body, including the toes.
Spinal cord compression: This can be caused by a tumor, infection, or trauma, and can lead to numbness, weakness, and loss of bladder or bowel control.

Leprosy: This is a rare bacterial infection that can cause numbness, tingling, and skin lesions on the feet.
Amyloidosis: This is a rare condition where abnormal proteins accumulate in the body, causing damage to various organs, including the nerves.
Vasculitis: This is a rare condition where the blood vessels become inflamed, causing damage to the nerves and other tissues.