Excessive hair loss accompanied by scalp itching often points to conditions like seborrheic dermatitis or a fungal scalp infection. I recommend starting with an over-the-counter medicated shampoo containing Ketoconazole (1% or 2%) or Zinc Pyrithione to help calm the itching and inflammation. Please avoid using hair regrowth treatments like Minoxidil right now, as they can further irritate an inflamed scalp. Because resolving the scalp irritation is key to stopping the hair shedding, I highly recommend consulting a dermatologist for a proper physical examination and a targeted prescription plan.