Thank you very much for your detailed note. I am glad that I may be on the right track on internal and external factors. On the forgeign factors, I would appreciate if you give me some guidance how to find out the irritants.
My baby is very itchy whenever she wants to sleep(being held by us because she needs us to curdle her to sleep, and I doubt it is our clothes, but we have also tried to use 100% cotton. Is it because of the washing powder we use in adults clothes? Is it because of sweat? I tend to think that when she is upset or lonely, she will feel itchy, kind of emotional/psycological reaction.
One thing I notice that she is extremely hot and it seems it is due to her internal body, especially when she feels irritated, itchy and crying. When we try to stop her from scratching, the itchiness intensifies. Sometimes we need to use fans to cool her down and it does help sometimes.
I remembered that her rashes comes out the first time when we bath her in excessive Johnson baby bath, and maybe the synthetic clothing we gave her to wear worsen her allergy. We have already thrown aways those clothes.
I do notice when she is put on the bed covers which do not feel so comfortable(may be due to dyes/material although all are 100% cotton), she starts to scratch faster than when we put on more comfortable bed covers. I wonder whether anti-dust mite bedding materials or organic cotton materials is better if I were to try one of these.
We have a dog at home, but we have locked her out in one of the room since arrival of baby most of the time. The dog seldom comes out into contact with the baby at all. When the baby is brought back to my home(Baby stays at mum's place during daytime where the dog is kept), she shows the same reactions and itchness. So I guess it might not be due to the pet.
Besides the above obervations, I can't think of any more possible factors. I would appreciate if you could give me some hints.