Many head lice infections cause no symptoms, and probably less than half cause itch. So you have to LOOK to find out if your child has head lice. Do not rely on itching and scratching. Newly laid eggs are usually within 1.5 cm of the scalp while older eggs are higher up the hair shafts. If you are not sure whether an object you find is a head louse egg, try sliding it up the hair shaft using your fingers.
Eggs are usually quite difficult to move, whereas hair muffs and other items slide easily.
However, finding live lice can be difficult since the climbers move away quickly from disturbances in the hair, and they are very difficult to see. Detangle the hair using an ordinary comb. Immediately comb the hair with a fine tooth comb. The best comb for this is the Lice Meister comb. However, plastic nit combs with conditioner are also very effective for detecting climbers.