Hi, The patch on your knee joint is Psoriasis. It commonly occurs on elbow & knee joints but also can occur on other areas of the body. Consult me online for proper medication
Next Steps
Would need more details about medical history and if any other areas of the body are affected
Health Tips
Use a rich moisturising cream twice a day
Take omega-3 & zinc supplements
Drink plenty of water
Use a mild soap or body wash for dry skin