Hi, Welcome and thanks for posting your query to Healthcare Magic. After reading your query I can make out two possibilities- one of the fungal infection and the other of discoloration due to hematoma. Now big toe is one of the common site for the fungal infection due to heat and humidity by wearing shoes. So fungus can grow on this site and results in kind of discoloration which you have. This can be treated by oral anti-fungal tablets taken for multiple months. The other possibility can be of discoloration due to trauma. Our big toe is again prone for the injuries so some times due to trauma there is blood collection over this site leading to discoloration. There is no meed of any treatment for the same. It disappears by its own in few weeks of the period. For the best of possibility you meet a dermatologist who can closely examined guide you accordingly. Hope these informations will help. With good health wishes Dr Sanjay Kumar Kanodia MD (Dermatology & STDs)