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It seems to be urticaria
according to the description.It manifests as red patches
above the skin level associated with itching.The most common reason for this is allergy
to any kind of food stuff or to pollens or any contacts(dust & dander
). It can also be triggered by any sort of infection in body like tooth decay
,stomach infection or any fungal infection in the body.So,its important to rule out any infection too.
The best test would be immunological testing giving a blood sample ,which would test for all the food items ,pollens ,contacts etc.It is better than a prick test.
treatment consists of avoidance of the suspected allergen ,anti histaminics ,immunotherapy injections & desensitization.
So,please don't panic ,its not a cancer.But usually its a long term treatment.