Talk to Dermatologist on Chronic Skin Condition, Itching, Redness And Scaling

I am a 23-year-old male and have been suffering from a skin problem for the last 3 years. It first appeared on my scalp, then my chin/face, chest, and now the left side of my scrotum. The affected skin develops dandruff-like flakes and severe itching. Scratching causes redness and red spots on my chest. The skin on my left scrotum has also become thin, dry, and shiny like plastic, while the right side is normal.

Please help me identify the cause and suggest the appropriate treatment. Could it be psoriasis, eczema, or a fungal infection?