I have had a similar problem, but have been able to isolate it to my work environment. http://www.cips.msu.edu/diagnostics/profiles/birdmites.html
At first they seemed to be everywhere. At home and at my work. However now I decontaminate myself as soon as I arrive at home. Eradication is not easy, first you must find the source, mine was a dead bird, and a dead rat above the ceiling tiles. Then you need to systematically treat and retreat the source with pymethryns, also trymethryns work well. I still have not completely eradicated them from my work environment. However I spray my lower pants socks and shoes with a product called Deep Woods Off containing an active ingredient of 25% DEET as soon as I get to work, and usually retreat myself after about 4 hours. I have also found that using tiny amounts of pymethryn applied on my skin after a shower to be helpful if I get a bite.
When I say a tiny amount, I mean tiny. Typically when I used elimite which is 5% pymethryn. I would place a dot or two no larger than 1/4 inch
and rub it all over sill wet skin after a shower. Be sure not to miss the soles of your feet. When I ran out of elimite I made my own formula using one ounce of RID a common lice removal product added to a small 6oz container of skin creme. Again, I only use two small dots of this stuff on wet skin after a shower. Then I lightly pat myself dry with a towel.
I can not recommend this treatment for anyone else because long term uses of pymethryns are not recommended.
I also found on a web site a way to find where your heaviest contaminated areas are. Place black construction paper vertically in different areas around. The mites will crawl to the top edge of these surfaces and can be seen under magnification.
I am currently investigating the use of soaps with sulfur in them. It seems that these bugs ( which are actually arachnids) do not like sulfur, and I certainly want to discontinue any use of permethryns as soon as possible.
I am a professional computer person, use to analytical thinking, and solving complex problems through the use of dividing the issue until what remains is the source or cure of an issue. I do not have any medical training, and am posting this information strictly as observations of my personal fight against this condition.
1.) Attack the problem at it's source, find the cause of the infestation and remove it from your environment. It's not enough to just remove the dead bird or rat. The nest and any contaminated area must also be cleaned.
2.) Try using insect repellants containing DEET.
3.) Vacuum carpets, and furniture, or steam clean. I add a tiny amount of a product called ZEP Pest control concentrate to the steam cleaning solution this product contains trimethryns a synthetic pymethryn, use less than 1/2 ounce in two gallons of water. More is not better.
4.) Expect this to be a long battle, complete resolution of this issue can take 6 or more months.
PS Useful information.
These insects are probably not under your skin. When they bite they release a compound that liquifies skin. The severe skin reaction is from the feeding tube left behind. However, I personally believe that in some cases, possibly with people like myself who exhibit allergic skin reaction to certain things, and have dry skin, they may be able to get under the skin.
I believe the white dot you refer to are these mites in their larve stage.
Pymethryn is a natural inscectiside derived from flowers. Trymethryn is a much stronger synthetic form of pymethryn.
These pests are highly mobile, don't let their size fool you. They and travel from the bottom of you shoes to the top of your heat in about 15 minutes. The equivilant of a human climbing Mount Everest in about the same time.