I would suggest taking digital images (close-ups) of the red spots, with a ruler placed within the frame. There is a good chance they may disappear when you are examined.
The question as to whether you need to go to an ER is a good one.
There is no easy answeer to that. Many ER's do not have a dermatologist on duty.
My gut feeling is that is is necessary to "Rule Out" a systemic infectious agent. It could be fungal, or viral.
If you are not satisfied with a provisional diagnosis when you have your appointment, do not hesitate to seek a second opinion.
I would also, in the mean time, take the cautious route, and assume the condition may (and I emphasize may) be contagious. This is also something to discuss with your physician.
Hi
Welcome to the MedHelp forum!
It is very difficult to diagnose an itchy rash like lesion without a clinical examination. The various possibilities of a round itchy lesion is varicose dermatitis (occurs over a varicose vein), discoid eczema (this may be both the dry or wet type), asteatotic eczema or a variant of discoid eczema over dry skin, atopic dermatitis, contact dermatitis, or even psoriasis and tinea corporis (a fungal infection). All the above mentioned conditions can worsen on scratching and have a recurring course.
The red spots could be tiny bruises. Deficiency of Vitamin B12, folic acid, or Vit K could be the cause. They could also be fragile spider veins. The spots could also be petechiae, which are pinpoint-sized red dots under the surface of the skin. They can result from autoimmune disorders, such as lupus or rheumatoid arthritis, bone marrow disorders such as leukemia, inflammation of the veins, as a side effect of certain medications.
If along with spots there is itch, then it could be contact dermatitis due to material of a cloth or soap, powder, deo, perfume etc.
Do discuss this with your doctor and get yourself examined. You will need to consult a skin specialist regarding this. If the rash worsen go to the ER. Try and eliminate causes of contact dermatitis until then. Take care!