I am going through something so similar with my dog. She has been itching and scratching for the past couple months. Her eyes also water, but they do that a lot. I tried and tried to figure out was was causing the itching. I thought it was because I had changed the brand of "cookies" I was giving her. I went back to her old ones and nothing changed. Then I thought it was her food. I give her a little bit of dry food in the morning in case she gets hungry during the day (she hangs out outside all morning while I'm getting ready for work, so she doesn't eat in the a.m.). I noticed during the summer she started eating the dry food every day and even on the weekends. That was very unusual for her. The color of her food seemed to be darker. I went on Nature Variety's website to see if they changed the formula. They added a new plant this year and said that dogs used to only one protein may have temporary digestive problems. That led me to believe that they are making multiple products with the same equipment and wondered why they would do this at the new facility but not their others. I thought maybe there was something that she was allergic to. I started feeding her something I knew she was okay with and nothing changed.
She has had shorter bouts of this itching before. She gets it when I give her humawrom for pets (herbal parasite cleanser). She got it some early in the summer, and I thought it was from something the groomer used on her (about the same time). It went away after a week or two. Then later in the summer I had started giving her Colloidal Silver . Among other things, it kills parasites. I now believe the crazy itching is from the toxins being released from the dead parasites. I quit giving her the Colloidal Silver even though she absolutely LOVED her water when I put it in -- her water intake was noticably higher with the Colloidal Silver in it. I gave her the humaworm again, thinking that she must really have a lot of parasites. Anyhow, this has led to a couple months of terrible itching. Neighborhood cats come into my yard and pee and poop. I feel they are constantly bringing in parasites. It's almost like Haley is constantly being infected with them. I think they must build up so much that when I give her the humaworm or colloidal silver, the toxin release is very high from the large amounts of parasites being killed. I could be wrong with this theory, but it makes more sense than anything I've been able to come up with. I read an old thread on the humaworm forum where people were giving their pets the humaworm every month. I thought I could only give it to her every 4 months (so the parasites don't become immune to the herbs), but I think it would help tremendously if I could give it every month -- wouldn't allow for such a large build-up of parasites.
I've given her claritin and benadryl at different times. I've sprayed her with an apple cider vinegar / water mixture. I have rubbed coconut oil on some spots. I have sprayed colloidal silver on her. I put an oil product (salmon, flaxseed, and something else) in her food. I just started putting therapeutic living clay in her food several days ago ("attracts" the toxins and helps remove them from the body), and this seems to be working the best. Right now I am giving her the clay in her dinner and rubbing some lotion on her. It is Miracle II and doesn't have all the crazy chemicals in it. I also gave her benadryl last night before bed. I think the clay is having the most affect.
I asked people on humaworm about giving it every month. Nobody who talked about doing that before has responded, so I'm not sure yet. Right now I just want to get rid of the itching and then will later worry about dealing with the parasite issue. Also, her eosinphils (sp.?) have been high on most of her blood test results (I get blood work done on her a couple times a year --- had health issues with my last dog and had wished I knew all levels of everything earlier and could compare as things worsened). The high eosinphils can mean many different things, but one thing is parasites. The only time hers hasnt' been high was when she had the blood work done about 2 weeks after taking humaworm last winter. That leads me to believe that it is parasites.
Good luck with your baby. I know it's awful to not be able to help them. Haley has started getting bright reddish areas from biting and scratching. It almost looks like she scraped it on cement or something. I quit using the apple cider vinegar when I started seeing these areas. Her body also feels hot, too, like your dog.