I lived in the tropics for 50 years and know how to deal with mosquito bites to where they are not a bother. If I get bit I put Purell hand sanitizer on the bite and it goes away within the hour and you never remember it again. My children get bit, they put on Purell, end of story. However, now I have a little daughter of 5 that get's huge welts from the bites and my wife has to keep her indoors for 3 days and give her Benadryl to bring the swelling down. The little girl loves to be outdoors, but the mosquito bite reaction is stifling her activities. We do not want to use Deet or other mosquito repellents unless there is no other remedy. We do spray her clothes sometimes with natural repellents that work, but the mosquitos still get her and just one bight and it's back to Benadryl and no outside for like three days. Any remedy ideas out there?

By the way, for wasp and spider stings, I was taught to use cigarette tobacco and spit or water. You sprinkle the tobacco on the bite, wet it, and put a bandaid over it to hold it in place. You will get absolutely no swelling and when you go to take a bath and remove it, you will see not a sign of the bite. I've thought of trying this on mosquito bites on my daughter but being little, she does not notice the bites till it is too late.

Sorry to hear that.  I have a couple of kids who react the same way.  I myself can get stung a hundred times and I feel slightly itchy and that's it.  No welts at all.  I go picking blackberries and get swarmed by hundreds and don't react.  But a couple of my kids get it bad.  I'm also immune to poison ivy whereas my wife a a couple of my kids need to go on oral steroids from the smallest contact.

There are some natural things to try ...
https://www.healthline.com/health/kinds-of-natural-mosquito-repellant#lemon-eucalyptusoil

This one says that a certain mixture of lemon eucalyptus oils provides 95% protection for up to 3 hours.

I lived in the tropics for 50 years and know how to deal with mosquito bites to where they are not a bother. If I get bit I put Purell hand sanitizer on the bite and it goes away within the hour and you never remember it again. My children get bit, they put on Purell, end of story. However, now I have a little daughter of 5 that get's huge welts from the bites and my wife has to keep her indoors for 3 days and give her Benadryl to bring the swelling down. The little girl loves to be outdoors, but the mosquito bite reaction is stifling her activities. We do not want to use Deet or other mosquito repellents unless there is no other remedy. We do spray her clothes sometimes with natural repellents that work, but the mosquitos still get her and just one bight and it's back to Benadryl and no outside for like three days. Any remedy ideas out there?

If you don't mind eastern medicine, NAET worked for us.
Check it out at naet.com
Treatment from an acupuncturist trained in NAET worked much better for us than from a chiropractor. 

We successfully use homegrown aloe vera arborescens.

I have aloe vera plants on my property, how do you use it and how does it work on mosquito welts. The child gets big lumps, about the size of a silver dollar and 3/8" high in the middle.  

I have aloe vera plants on my property, how do you use it and how does it work on mosquito welts. The child gets big lumps, about the size of a silver dollar and 3/8" high in the middle.

That's a different species, probably aloe vera barbadensis and not aloe vera arborescens. It basically contains the same active substances though in different quantities/ratio.

For usage see e.g. https://www.liveloveraw.com/what-to-do-with-aloe-vera/
Or google "preparing aloe vera" or "cutting aloe vera".

@Last Tradhican

Did you try that Aloe Vera of yours? Any results?

@Last Tradhican

Did you try that Aloe Vera of yours? Any results?

Amazingly, the little one, 5 years old, has not been bit since I wrote asking for suggestions, her outdoor play now is in an Intex above ground pool after school (homeschool kindergarten). I have to remind her to tell me right away when she gets bit, because up till now she does not notice the bites when she is playing and it isn't till the next day that my wife finds out and then it is too late. I want to catch it early on, like I do with wasp stings, where I use wetted cigarette Tobacco. I'll let you know when I get to test your Aloe Vera remedy.