What are the most common skin diseases-->>see details

i am doing a project on skin diseases but there are more than 80 and my project needs to be limited to at the most 40 pages. does anyone have a list by any chance on what are the 30 most common diseases. Please cooperate!

I can give you a list of 30 or more. But you can surely be able to write 40 pages using 5-10 different rashes. Most common: acne, seborrhea dermatitis, contact dermatitis, psoriasis, eczema, tinea infections (athletes foot, jock itch, toe/fingernail fungal infections), warts, dyshydrosis, dry skin, and diaper rash.