Our 11 year old spayed female dog Hintza has some sort of itchy skin situation on her rump. At various times, she'll be jolted into intense bitting the area in order to relieve some sort of itchiness. Upon inspection, we find very pink skin and three to four small bb-sized raised areas. We see no critter invading her. No fleas. We've been putting a topical Chinese Herbal product called "yin care" on it. That seems to soothe her for the moment. But what is the cause, we wonder? We live in Baltimore Maryland in the city. We don't think that it's chiggers but her reaction reminds me of what I have felt when I've had chiggers. Any ideas about what this is? And might help get rid of it? We noticed it about two evenings ago, but the yin care calmed it that evening. Thank you for your wisdom and experience.