Wow! Two years ago when I started suffering from these same symptoms described by many on this post, there was nothing to be found. I have not actively pursued finding the cause, it was just something I encountered from time to time. The itchy palms and feet were always a common denominator, usually followed by a transient swelling that would show up in different parts of my body. Sometime in either forearm, back and base of my skull. The swelling was usually followed by soreness in the affected areas - similar to a bruise or "charlie horse". Over the last week, though, it appears as if my body has gone into meltdown, and I had significant swelling in my face, first in the sinuses under my right eye, then to the lips and jaw the second day. It then moved to a large swollen area on my right forearm, the right side of my back between the shoulder blade and spine and several lumps in a perfect row going down the back of my left thigh. Yesterday, the swelling moved to my left forearm, and looked like someone grabbed my arm to tightly, and left red hive-looking things. Today, it's still on my left arm, in a large area. The deep (maddening) itching in my palms and feet wake me up repeatedly throughout the night (particularly at night it seems), and often burns afterwards when I try to scratch it. When I do, the swelling worsens and it is hard to walk the next day because they are so tender.
I have started to look at my diet, since the nature of the reaction seems to be allergic in nature. I am not sure, but I think I have narrowed it down to corn products, particularly if it is processed. I don't seem to notice the reaction when it's whole corn (I assume since it passes through the digestive system generally unscathed...) I am going to get allergy tested soon to see if this may be the cause (I hope!!). I recently moved back to Texas, although these symptoms started 2 years ago when I lived in Utah, and have also experienced them in Arizona.
This most recent incident, I did try taking antihistamine products (double the suggested dosage), but they didn't seem to touch it. This is one week later, and I am still experiencing the symptoms (although this was by far the worst reaction yet). I am going to start with a good look at my diet to see if this could be an underlying cause. I have heard it said that we can develop food sensitivities, which are similar to allergies, and much more common. With corn (and wheat) being the cornerstones of processed foods, it is worth a shot...