The last itchy baby sleep post was from me. I've tried a lot of the suggestions. I've got a little routine down that seems to be helping...
1. Rx Allergy Meds.
Everyday I give him Rx Zyrtec.
On bad days he gets either Benedryl or Atarax before bed. The suggestions to try Atarax did help... but dr said it is not as safe as benedryl so I try to use only when really needed.

2. Bath Routine.
Once per week bleach bath - Every other day Oatmeal bath made from grinding 1/2 cup quaker oatmeal (aveeno is too expensive when you are using it this much) - 2 x per week regular bath to wash hair. After bath baby oil then lots of Eucerin or Aquaphor(walmart generic)(the kind that is in the round tub)

3. Whole house humidifier set to about 45% humidity.

He's doing great with these steps but it takes ALL of them as well as making sure he stays away from the things he is allergic to.
I think changing seasons is very hard for my skin so assume it is for him too. Humidifier helps. Oh yes footed PJs help too but getting overheated makes it worse. So I keep the house set on 65.