Whats could be causing allergic reaction after blood tests come back normal

[Smudger1959]

Since aug, on and off, my face , eyes,lips and above my mouth has been swelling up. My eyelids have also been very red and sore and ive had red dry patches all over my face and this week on my neck. It hasnt happened any other place on my body. I ve had blood tests , all of which were ok, no allergies. I ve stopped using all make up creams and hair dye. I havent started usung different washing powder etc. I ve been prescribed anti histamines and because my face swelling was so sever this week i m now on a short course of strroid tablets. I didnt take antihistamines yesterday as wasnt sure could take with steroids andcthis morning my bottom lip is swollen. My tongue feels tingly and my throat feels a little swollen. Dont no if this is the allergy or i m getting a sore throat.so i ve taken an antihistamine just in case I ve been referred to an allergy clinic.. Any advice is appreciated . Thanks