If I was you, I'd start with some pyrantel (PinX), eat plenty of fresh pineapples, and do daily enemas.

Sounds like you have pin worms because of the itchy anus. I suggest that you do research on them specifically because you have to do a lot of cleaning and laundry to get rid of them. You may have to treat everyone in the household.
I would recommend Dr. Andreas Kalcker's protocol. You need a protocol because getting rid of parasites is a long term project. Just google him. He has an 18 page free PDF on parasites. You can also read the book Healing the Symptoms Known as Autism by Kerri Rivera by Kerri Rivera and Andreas Kalcker and others. There is a direct link with autism and parasites. There have been a couple of conferences on autism that are on YouTube with very useful lectures. AutismOne 2014 is one. The 2015 conference is good too.
I have a blog on this site. I think I am successful but the results won't be known until the next moon cycle when I start my protocol again. My first blog posting has my protocol. I update it as I find things that work or don't. The blog is Getting the parasites Out- #4190. It's a protocol that I worked out with my doctor who is a naturopath. It is also the result of a lot of personal research. It is different from Dr. Kalcker's protocol because it can take some time and research to get the drugs he uses-mebendazole and chlorine dioxide. They stopped selling mebendazole in the US a few years ago for mysterious reasons. The chlorine dioxide is an underground remedy. Go to Jim Humble's website for suppliers. And don't believe all the troll postings about it being bleach.
I had some really bad breath when I had a lot of die off of parasites.
You may get rid of the eczema when you get rid of the parasites because you have to clean up your diet to be successful. Our Standard American Diet is full of toxic chemicals. You have to go organic.
Good luck.

My 1st step was to get me going to the washroom as much as possible. Green juice or liquid chlorophyll worked well. I passed MANY parasites just by passing them naturally.

Then I did my first round of hydrogen peroxide therapy. That got rid of everything, until I went to mexico. Then I had to do it again :)

I suggest looking into candida no doctors won't diagnose you unless it's oral, vaginal, or your immune compromised ...but my family and I have dealt with similar issues for 2 yrs and took many parasite cleanses and antihelmetiics to be allieved for only a couple of days and no these candida cleanses are not the answer and it takes up to a year of treatment but I do suggest reading an article by Walter Last "candida and the Antibiotic syndrome" very informative also looking into symptoms caused by candida you will probably solve many past health related problems or those u love good luck there is a lot of info so don't just read one article