Red blotchy rash on my arms neck back and stomach?

probably an allergy. With this distribution and without symptoms of infection like fever, malaise or joint pains this probably represents an allergy. Diagnosis would depend on the appearance and distribution of the rash. See your dermatologist.

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After tanning I developed red blotchy rash on neck and a prickly skin color rash on inner arm?

Check this out. If this has not gone away I would suggest checking it out. It's hard to say what this may be without seeing it. Skin cancer is always a possibility. Also, a biopsy may be necessary. Read more...