welcome to healthcare magic forum
thank you for your query
over body may be due to many reason .
it may be due to allergy
we have to find out the reason for it
as you have no itching ,chance of allergy is less.
but in some allergy you may not feel itching also.
i would like to suggest consulting dermatologist
for proper management .
you can apply calamine
lotion over skin.
in some infection also we found similar redness also .
i hope i answered your question