It sounds like you are having an allergic reation.

"Itching" Your Body's Automatic Healing Process
There are many automatic systems within your body including your healing processes. Your heart beats automatically. You breathe automatically. And your body's "Automatic Healing Process" is another. It is activated when your body produces an itching response to the needed and necessary areas. You then will automatically scratch that area, it in turn, turns red with a fresh blood supply and the automatic healing process is under way.
http://www.racingsmarter.com/skin_brushing.htm


Skin brushing activates your body's automatic healing and immune processes. It is the sensation of itching that cues you to your body’s desire to activate the healing process to any one specific area or region. Itching occurs on its own or during and sometimes following skin brushing and is a reminder that scratching or brushing is necessary. The "Itching Cue" is a vital part in the process for toxic conditions and for tissue repair and recovery from injuries. Itching will occur over a new injured site as well as old ones. This automatic cue to the healing process helps the body provide the best quality of tissue repair as well as helps prevents unwanted fibrous tissue formations. So, both scratching with your fingers or by skin brushing are excellent ways of activating your body's natural healing inflammatory process. This amazing healing mechanism is incredible to watch and to be a part of as it helps maintain or accelerate the recovery of sick and injured tissues in your body back to health.

I had something similar, stress-related, food-allergy related eczema. The anti-canddia diet works, as does food allergy avoidance and majorly destressing, at least that's how it went for me. I've also heard of people having a poor response to ThreeLac, because of fecal impaction.