Please tell me, could fleabites cause cellulitis and what is it?

Yes..., Inflamation: Fleabites could result in a cellulitis. Cellulitis is an inflammation or infection of the soft tissue resulting in redness, swelling, and possible pain.

Not directly: Fleabites directly do not cause cellulitis. However there is surrounding inflammation which can become itchy and if you scratch these bites you can transfer the bacteria from your nails into the flea bite. This can then become infected and cause cellulitis