Dandruff after shampooing may be related to bad habits, tinea capitis, asbestos chaffing, seborrheic dermatitis, psoriasis and other conditions, which need to be relieved through life conditioning, medication and phototherapy according to the cause. 1. Bad life habits: If you use irritating shampoo for a long time, it may lead to dandruff. You need to change shampoo and use neutral or acidic shampoo. 2. Tinea capitis: patients with tinea capitis can take oral itraconazole, ashwagandha and other drugs, together with the application of ketoconazole cream, salicylic acid ointment and other medications. 3. asbestos chaff rash: this kind of patients will also appear in the scalp small white chaff rash, patients can take oral zinc sulfate, vitamin A and other drugs, but also can use coal tar shampoo, and then with the application of sulfur ointment treatment. 4. Seborrheic dermatitis: Seborrheic dermatitis will appear in the scalp area itching and dandruff. You can take roxithromycin, vitamin B2 and other drugs, and if necessary, you can use ketoconazole lotion, selenium disulfide lotion and other drugs to treat it. 5. Psoriasis: Patients with psoriasis will have a lot of white dandruff, which can be treated with medications such as retinoids, methotrexate, cyclosporine A and so on. If necessary, it can also be combined with phototherapy to alleviate the symptoms. As many causes can lead to dandruff after washing hair, patients should go to the dermatology department in time to get a clear diagnosis and standardized treatment under the guidance of the doctor.