Hi, You said you have hypermelanotic skin on elbows,knees ,buttocks and genital areas. It seems that it may be hereditary. It may be due to your constitution. It may not be due to any disease. So, I think you should not to worry about hypermelanosis. But, I can understand your concern about dark skin. Cosmetic point of view, you might get treatment. You consult dermatologist for firm diagnosis and treatment. You may take vitamin E,vitamin C, nicotinic acid and glutathion for long time. All this drugs might reduce color of affected areas. You may apply kojic acid and vitamin C contsining gel. Have nutritious food to have sufficient vitamins and minerals. Have positive attitude. If the color remains unchanged or get poor result, please accept it without worry..as it is harmless. I hope you got my answer. Thanks. Dr. Ilyas Patel MD