Went on a trip to Koh Chang BKK and home. Stayed on the beach and a couple of hotels. Been bitten all over. Suppurating bites. Clearly not mosquitoes or even fleas.Doctor/Hospital has not a clue. Tried to get them to take a blood sample from the wound ..no chance...What apart from mozzies/fleas/bed bugs could bite you like this? Antiseptic/anti=inflammatory creams don't work not even my beloved Tiger Balm....aaaargh!! Any thoughts

Almost certainly sand fleas. They are far worse than mosquitos. Have a look at this blog

http://www.onedayinacity.com/preventing-sand-flea-bites-while-traveling/

Sand fleas or bed bugs are the two most likely things.

In either case, applying hydrocortisone cream or other steroid cream (betamethasone etc) should bring relief. If the bites look at all infected, clean first with an antiseptic (betadine etc) and make it a steroid cream that also contains an antibiotic. If it does not look infected, just the steroid alone.