swallon face and all over body rash

hi im new to med help! i just woundered if anyone could advise me due to a rash my mum as developed, the rash first began small itchy and red around her neck she went to the doctors and they said it was an allergy to wooden jewerely, since then she didnt wear any but as the weeks proceded the rash spread all over her body became reder and itchy, it looks like heat rash but lumpy and red. she as had this rash for about 3 weeks know the doctors do not know what it is or whats causing it! days later her face blew up like her ballon her face is that swallon it looks painfull this race is rapidly increasing worse and worse each day!! if anyone has had similar symtoms (symptoms) and has been treated, or anyone as any advise please let me no!!! thank you x