My skin is so rough and it makes me scratch alot...

Treatment : 
Simple lifestyle changes can help prevent and relieve dry skin Try to avoid using hot water to shower , shower every other day instead of every day , keep your shower time to less than 10 minutes , use a moisturizing soap when you shower , apply moisturizer immediately after showering ,  pat, rather than rub, wet skin dry with a soft towel , avoid itching or scrubbing dry skin patches , use a humidifier in your home like Pepantine cream , drink plenty of water , you should followas these instruction and  use moisturizer , if this fail , you should visit the dermatologist doctor to to examine you and giving a medical treatment regarding to your case
Diagnosis :
By taking full medical history anfd doing clinical examination and CBC to detect infection and blood salt to exclude dehydration 
Causes : 
Dehydration 
allergy
skin infection
fungals 
Advice  
you should visit the dermatologist