Dear Student,
Kwashiorkor is the disease that is mainly caused due to deficiency of protein in diet whereas marasmus is the disease that is caused due to deficiency of both carbohydrate and protein (predominantly carbohydrate) in diet.
Kwashiorkar: Swollen abdomen, thin muscles, underweight, reduced growth, reduced resistance to infection etc.
Marasmus: Thin muscles, thin arms and legs, low body fat, reduced resistance to infection, very underweight.
Regards