Insect bites and stings are commoner in summer when the numbers of bugs increases dramatically. Mosquitos are a common cause of holiday discomfort. Remember that mossies start to bite in the evening, so this is the time to cover up or to use effective insect repellants, particularly those contacting DEET, which is a powerful anti-mossi spray. Concentrations of 25% are often effective, but higher concentrations are also available.
If you or your children get uncomfortable bites try these simple measures: Apply a cold compress, such as a wet flannel that has been in the fridge or freezer for a while. Try this for 10-20 minutes every hour or two. If you have some oral antihistamines such as cetirizine, loratidine or chlorpheniramine (e.g. Piriton) then take them. Remember that chlorpheniramine can be sedating so this is a good one to take before bedtime. Topical steroids such as Eumovate cream or 1% hydrocortisone applied twice a day may be helpful.
A useful trick for children is to put a little moisturiser in the fridge and allow them to apply it when they like. The placebo effect can be quite powerful! If you develop very significant swelling or blistering then you may wish to see a doctor who might prescribe a strong steroid cream, or even steroid tablets for a few days.