sometimes it's because u don't wash your hair enough.
Dry scalp.
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If you do not wash your hair, your hair will get REALLY greasy and thin. It will get frizzy and staticky and you will look horrible. Also, you will get BIG painful pimples on your head preventing you from brushing your hair and your scalp will dry and flake.
The scalp could be red from rosacea or an allergy to shampoo.
Poor hygiene?
When your hair is relaxed and overprocessed.
Nits? Is that an answer or a question. There could be a hundred causes but the most common causes are oily scalp, not clean, dry scalp, dandruff. The list goes on and on. If you can;t seem to get it under control, you should see a dermatologist.
Really anything, it can be caused by a food or a smell or also reading. Don't think it's your brain its actually the viens between your scalp that are swollen.
your scalp (the skin on the top of your head)
Could be an insect bite.
Dandruff is a fungus that grows on every ones scalp
The most common cause of a flaky scalp is dry skin. A skin condition called eczema can also cause one to have a flaky scalp. Dermatitis and psoriasis can also lead one to develop a flaky scalp.