For the last 5 months, I have been having patches of skin (upper back of arm and/or back of neck) that have started severe itching and gets very hard and warm to the touch, anywhere from 2 to 4 inches in diameter. Always 2 spots at a time within a few inches of each other. This has happened at least 4 times, lasts for about 10 days or so. I a 66 years old, female and other than over-weight and seasonable allergies, in good health. Do not take any prescription medication. Could this be shingles?