I am suffering from Leucoderma since 20 years. I have started doing Kapalbhati and anulom vilom for 15 min each. Is this enough?

For Leucoderma which is there for 20 years 15 minutes of both pranayam would be a good start!! Eventually it would have to be increased to 30 minutes each and also would need other pranayams to be done. If you want the results sooner then do these twice a day, 15 minutes each is for healthy people to prevent any problems.