Nits are the tiny, oval-shaped eggs laid by lice, which are small parasitic insects that live on the scalp and feed on human blood. These eggs are usually yellow or white and are often found attached to the hair shafts close to the scalp. Nits can be mistaken for dandruff, but they are firmly stuck to the hair and cannot be easily brushed off. When nits hatch, they release baby lice, which can lead to an infestation. It's important to check for nits if someone has been scratching their head frequently, as this can be a sign of lice. Treating nits usually involves special shampoos or combs designed to remove them effectively.