question: Hi Doctor, would it be possible to have allergies on shampoo?  Been using this brand before and I just stopped because I tried on a new brand and then I went back again to use the same brand. Then it sort of my scalp is starting to itch and I can feel itchiness all over my body.  But I have no rashes or anything.  Just weird itch all over.  Can I take celestamine for it and how for long?  Thanks