dandruff
The German word 'Schuppen' is used to refer to dandruff. It can be used in a similar way to the English word, such as in the context of hair care products that help to control dandruff. For example, 'Ich benutze ein Shampoo gegen Schuppen.' (I use a shampoo against dandruff).
I have built a shed in the garden.
In this context, 'Schuppen' is used to mean a 'shed', which is a simple building used for storage or as a workshop.
Fish have scales.
In this sentence, 'Schuppen' refers to the 'scales' of a fish, the thin bony plates protecting the skin of fish.
Your hair has dandruff.
Here, 'Schuppen' is used to denote 'dandruff', the flaky skin on the scalp.