What could have caused crazy dandruff for 4 days?

I had crazy, crazy, crazy amounts of dandruff coming from my scalp for around 4 days, it was crazy crazy, crazy, much, then I used head and shoulders for one day and the issue totally resolved. I used to have a different type of dandruff that did not respond to anti dandruff shampoo or conditioners, but this type responded very well.

What could have caused crazy dandruff for 4 days?
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