I've had a similar experience. In April 2015, on a trip to Cancun group dinner in the sand I was bitten by sand flies (no seeums) on my ankles and legs, and arms. Those bites itches like crazy, began to oooze a Carmel-yellow clear fluid that would crust. It looked digesting. Clean it and it would ooze again. It dried up after about 2 days but continued to itch intensely. Last day of trip another dinner in the sand landed me with a few more bites. Get home and breakout in hives, large hives that are itchy the hives last a few hours then disappears. I have maybe 3 breakouts over a week and a half. The bug bites continue to itch for months. The two on my arm never go away and continue to itch off and on until maybe a month ago.
Fast forward to April 2017, trip to Aruba and another dinner in the sand lands me with new sand flea/fly bites. SUPER ITCHY!!!!! They begin to ooze. After a couple days they dry up and I breakout in large hives again only the hives are worse this time lasting a day and now my skin is ultra sensitive to everything! I was taking Benadryl then stated Zyrtec which helped but made me sleepy.
Went to an Allergy Asthma Immunology specialist June 12 he put me on a cocktail of Allegra and Zantac (1 dose of each 2times a day for 30 days). They can't test for things from another country but I'm also severely allergic to dust mites and roaches (mildly allergic to a few other things) which is no surprise to me because I've had a bug phobia since a child. Im always the person in the group when no one else is bit by something I'm bit multiple times. These bites as of today (July 10) on my legs and feet still itch like crazy! The 2 on my arms no longer itch and have flattened out completely looks like they are going away, after 2 years!
Side note I've been a Cancun, Aruba, and other island several other times haven't gotten bites and had no issue. Also, there were many others in our group that got these itchybites as well but don't seem to last as long as mine and didn't get the hives. I would like to get to the bottom of the problem and find out how I can get these itchy bites to go away and stop itching. Anyone else have any luck or have suggestions?