Dandruff can prevent hair from growing healthy and properly but having dandruff doesn't stop hair growth all together or cause loss of hair.
When you don't have dandruff your hair grows much better and stays healthier than it would when you do have dandruff.
When your scalp is affected with dandruff your hair also suffers from cuticle and protein damage more than non dandruff scalps.
Also the dandruff can cause scratching of your head which can further cause damage to your scalp and affect hair growth.
Still though dandruff is mostly just annoying and messy however it can prevent your hair from growing properly in some situations.