What Causes Red Itchy Scalp And Skin?

I am 58 year old male, 165cm, 70 kg. I never had any allergy before. I been using hair colour (same brand) about a year, never had a problem. Now on holiday in Vietnam I developed kind of allergy, very itchy scalp first but after few days itch spread to my my face,neck, chest, back and waist line. All these areas apear red. Worst is night time I can feel also my skin burning. I woke up with kind of short of breath. I took Telfast antihystamine tablets for a week but not much help. At times I have a goose bumps on my arms. Now I noticed also some red rashes few on arms and chest. Please help. (By the way I have some black tatoos on my arms for more then one year.) I also have mild Crohn desease.