Hello & welcome!
If you have any questions after reading my answer, be sure to let me know.
I am sorry to hear about your girls' problems
I would recommend that you should try to do the following things that will help
1. Prevent bites by using full length clothes especially when going out,
2. Use a good insect repellent cream whenever going out
3. Immediately at the time of an insect bite, apply calamine lotion liberally
4. Given an anti-allergic like cetirizine, again soon after any bite, before the swelling starts to increase
5. Sometimes in case of a severe reaction, it may be appropriate to use a mild steroid cream locally.
6. If these steps do not help, then an allergy
consultation for desensitization may be considered to reduce the local reaction,
Do get back for any clarifications, please leave a positive feedback if the advice was helpful,