Flea bites can certainly be very itchy because of the allergic reaction that they cause on the skin.
To alleviate itching, we always recommend applying a topical 1% hydrocortisone cream, which is a steroid that works exceptionally well at reducing skin inflammation and itching.
You can also apply calamine lotion to the flea bites as this will help to draw out any fluid in the bites and reduce itching.
Keep the flea bites covered with bandage or gauze in order to keep the topical medications in place without being rubbed off.
In addition, resist the urge to scratch the flea bites because this will not only remove the medicine, but it will also possibly break the surface of the skin and cause bleeding and possibly infection.