Long dandruff is not necessarily psoriasis, but can also be caused by a fungal infection. Psoriasis will have a very obvious triad of signs: silver-white scales on the scalp, which are thin, white, and large in amount, and come out in layers; after the scales are peeled off, there will be a very thin film; and after the film is peeled off, there will be punctate hemorrhagic dots. Ordinary fungal infections of the scalp, such as ringworm and seborrheic dermatitis, do not have this obvious triad of signs and may present with symptoms such as hair loss and itching. After the fungal infection, it is recommended to use topical antifungal lotion treatment, commonly used antifungal lotion is ketoconazole lotion. Dandruff, it is recommended to consult a dermatologist for treatment. It is important to change bad habits and wash your hair regularly to maintain hygiene.