Over the last year or so Ive noticed a rash under the arms. Predominately under the left arm. It is black in color but does not itch. I am overweight, high blood pressure using 2 meds to control and have been using Triamcinolone acetonide to control it. Comes and goes monthly to two months..
Hi, Rashes underarms are common due to blockage of sebaceous glands and could be due to an allergic reaction or side effects of certain medications. I would suggest you keep this area clean and Chat Doctor.  Apply a cream containing atelier acid. Apply warm compresses with a soaked towel. You should avoid touching or pricking rashes. If the condition doesn't get better than consult a dermatologist for proper examination and start treatment accordingly. Hope I have answered your query. Let me know if I can assist you further.