Hi Soul,
As jja says i concur totally. I had cholestasis of pregnancy with both and it complicates things enormously however i had no rashes. lots of scratches because you cant stop scratching all over but especially abdominaly(like a puppy with fleas)it is unbearable.
Still i'd have your tests done asap. It sounds s lot to me like a skin allergy maybe switch to low allergy wash powder and use sorbolene soap and moisturiser. HTH.
Pauline