Medical: "Id Reaction" to Poison Ivy

I have itchy red dots on my arms, legs, and along my spine. Here are your clues:

1. They appeared around August 23, several days after I got a 3-inch "stripe" of poison ivy just above my left ankle (around August 20), and shortly after a round of crazy antibiotics for my Pnuemonia
2. I never had a fever from this, so unlikely to be any of the usual "spots" viral diseases
3. They are symmetrical, generally appearing the same on the left and right sides of my body, even though they migrate up/down  to outer  and inner parts of my limbs. This suggests "an inside job" as the dermatologist puts it.
4. They don't look like lymph disease lesions, and aren't in the groin (where lymph stuff likes to go)
5. They don't look like Pityriasis Rosea (not red enough)
6. They don't seem to be a reaction to Bactrim or any of my other medications (they should have emerged closer to the time I started taking them
7. I've never had eczema or a rash like this (that I can recall)
8. The rash migrates: back of knee to front of knee to front of shin to back of shin at about the rate of moving to "the new place" every 2 days.  Same for elbow crease to elbow point to forearm inside to forearm outside.
9. The rash on my spine just sits there (as Pityriasis Rosea might, but not as colorfu)

I saw a Dermatoligist today.  His conclusion: My immune system is out of balance from the Poison Ivy.  He reasons:

1. Contact Dermatitis (Poison Whatever contact) can "go generalized" 
2. It is particularly likely to go generalized if it starts on the lower extremities (hard to get more extreme than the top of my ankle)
3. For an immune-compromized guy like me, it is very possible that even though I might be a little bit short of fighter cells, they can get into an auto-immune feedback loop and just  "keep fighting" if I happen to have a shortage of the immune "control" cells that might ordinarily calm things down
4. This generalized reaction is called an Id Reaction.

Were I not immune compromised, the solution would be oral steroids to force a calm-down and break the cycle.  But oral steroids can suppress the immune system, generally.

So the solution is a topical steroid, twice a day: covering every red dot with a white dot of cream (or rub on a concentrated area of dots).  Topical steroids do not suppress the general immune system, but have been shown to stop the runaway fighter cells.