Does this sound like a flea bite?

[boundarybabe]

The other day I noticed a couple of fleas on the cat (he is an indoor cat so one of us must have carried a couple in from somewhere) - he has been frontlined, combed to within an inch of his life and I have sprayed everywhere indoors

But DS (6 months) has an insect bite on the back of his leg which just appeared today. It looks like a gnat bite with a white centre and red around the outside. Does that sound like a fleabite?

could be a flea bite, but if you've done the spray everywhere it might just be the last 'attack' as flea's are dying off, so I wouldn't panic unless you found anymore bites

IME you don't tend to get just one flea bite - they seem to bite in lines iyswim?

yep - it sounds like a flea bite to me.
Fleas are insidious little creatures and their eggs get everywhere. Frontline only gets the fleas on the cat, they can still exist in your carpets and upholstery and new ones hop straight back on the cat again. Spraying is not enough IME you need to obsessively vacuum everywhere paying extra attention to areas of carpet along skirting boards and any place your cat sleeps.

Ask your vet about program, it is an injection for cats that renders any flea which bites to become sterile, thus breaking the flea life cycle. This coupled with all the above measures is very effective.