Can be because of multiple reasons..need more information..is that a sudden change or gradual?any swelling?Pls Consult a Veterinarian offline or online .

There is no harm in getting a consultation online or offline for such a situation . This cannot be judged without examining. There may be various causes of this varying from allergic to infectious. Get it checked and treated thereafter

It can be some allergic reactions due to floor cleaner, or it can be completely normal due to loss of pigmentation there. In case of allergies or infection, you will see itchiness or discomfort in that place. If he is not having any of those, then it may be normal pigmentation loss. For further confirmation, you can have a clinical examination with any veterinary doctor.