Thanks for posting your query.
From the history it seems you suffer from urticaria
. This means allergy which could be due to your miscarriage
which again is due to imbalance of hormones due to mis carriage.
You need to take antihistamines regularly like levo cetrizine
or anything else which suits you. This will be decided by your doctor. I can only assure you that it is only transitory and you need not worry about it. If it continues beyond two or three months you need to undergo a battery of tests suggested by your dermatologist