Head lice are highly contagious and can spread quickly from person to person. They are found in three forms: eggs, called nits; nymphs or immature lice and adult lice. Symptoms of a lice infestation include itching and scalp irritation. Infected persons might also feel a tickling sensation as the adult lice crawl across the scalp. It is possible to check the hair for lice using a simple procedure. However, unless the lice infestation is significant, you are more likely to find nits than live lice in the hair.
Position the light so that it shines directly on the top of the hair. Starting from the nape of the neck, carefully part the hair.
Use the magnifying glass to check the roots of the hair for nits. Look for tiny yellow, tan or brown dots. These are nits. Look for white or clear shells which are the shells of hatched nit eggs. Check the hair for sesame seed-sized or smaller spots that are grayish white or tan in color. These are nymphs and adult lice.
Move up the head, parting the hair into small sections and checking for lice and nits. Check the scalp as well as behind the ears. Examine the scalp every three to four days if you have come into close contact with an infected person.