Both head lice and dandruff can cause noticeable similar symptoms such as itching and white specks on the scalp. As head lice feed on human blood via the scalp, they can cause your scalp to feed, whereas dandruff can make you itch when the scalp is very dry.
However when head lice are present you may see some white movement on the scalp and nit eggs which appear stuck on the scalp. In cases of dandruff, the white specks will easily fall out and the scalp can appear yellow or white and may be scaly or oily. The causes of each are different however both conditions can be easily managed with proper care.