Hello,
It can be due to contact dermatitis or allergic reaction. Wash the areas several times with fresh water. Do not use any cosmetic products at the sites. You can apply some calamine lotion at the rash as it will help in soothing the skin. You can take some OTC oral antihistamine medications like Benadryl or Claritin and see if it helps.
For mild-moderate symptoms a weak steroid may be used whilst more severe cases require a higher-potency steroid. But they are available under prescription and should be taken only after consulting a dermatologist.
If the symptoms persist then get an evaluation done from a dermatologist.
I hope it helps. Take care and regards.
The rash seems to have gone a little after washing my bedding but I get it a little after waking up in the morning especially on my arms and shoulders. What are they?
Since typing this post the rash has appeared on on shoulders and a little on my arms. I've taken an antihistamine just to be sure. Its probably a good idea to see my doctor I think
I try uploading a photo but can't find a way to put in the post?