Bald patch - fleas?

Molly is 5 months old, and we have an ongoing battle with fleas.

I keep her frontline up to date, and literally 4 weeks to the day that she was last treated, the fleas came back. I checked with the vet and treated her again, and Roxy, and we are flea free. I have also treated the house, and the furniture. The vet mentioned that it takes 2 months to kills the cycle of fleas, so hopefully we've done this now.  

Molly lives with an indoor / outdoor cat - Roxy, so Roxy could be bringing the fleas in?

Just two days ago I noticed a bald patch on the back of her back leg. It's dry, not weepy, although it looks a bit scabby on a very small part of it. It's in quite a hidden place, and doesn't look new, so could have been there more than a couple of days. It's not troubling her, I haven't seen her worrying at it at all, and wondered if it's something she did perhaps when the fleas came back last week? Or when the frontline was working as that seems to make her itch? I'm checking on it several times a day, to make sure it doesn't get any bigger, or change, or not stay dry.

Anyone else experienced this?

I can't comment on the bald patch. You know to have your vet look at it if it changes, looks suspicious, etc.

On the topic of fleas - it takes at least 3 months of consecutive treatment to kill the flea life cycle is what I was told. I ended up treating my kitties for 3 months when I had a suspected flea infestation. I had good success with Diatomaceous (sp?) Earth in the carpet to keep fleas in the house at bay.

It's entirely possible the fleas built up an immunity to the Frontline, and you may want to treat for one month with something different. Roxy could be bringing fleas in on her. I'm not sure what the weather is like there, but here it just snowed a few days ago & the highs have been like 20-ish F. I don't think there's fleas alive outside here right now - thankfully!

Thank you! *sigh* it might take another month then! I've heard of fleas building up an immunity too. I may research into natural products too, I've heard lavender helps? And neem oil? Yep, I'm keeping a close eye on that bald patch. It looks like it might have some fluffy fur growing back *fingers crossed*

The weather here has got really cold, and it's going to get colder, -1 this weekend, hopefully that will help!