Thanks for your query
Your partner seems to have developed pityriasis rosea
It is a self limiting condition.
It usually follows viral illness mainly cough
Itchy red round to oval lesions seen on upper body.
Just apply a topical steroid
Can take antihistamines if there is itching.
You need not worry as it is self limiting.
Takes about two to four weeks for complete cure.
Hope it helps
Dr Geetika Paul