I have a c shaped rash on my right wrist. What could it be from? I noticed this rash on my right wrist about three days ago. Its a thin shaped c or u and itches like crazy. I have used hydrogen peroxide and cortizone cream for the itching, its not ge

Could be fungus. Fungal infections can be round in appearance. You could try over the counter lamisil (terbinafine). If it doesn't get better see your doctor.
Without . Without examining you and being able to see the rash first hand, it's difficult to say what it is and how you should treat it. -if it is a contact dermatitis caused by an irritative substance such as poison ivy, you want to wash the area well with soap and warm water and apply hydrocortizone for the itch. If it is spreading, worsening, or not improving after a week, you should contact your doctor for an exam and possibly stronger prescription medication. -if it is ringworm (a fungus causing an itchy, raised circular ring), you can try using Clotrimazole cream 2 or 3 times a day for the next few weeks. It may take 3-4 weeks to completely disappear and is contagious for the first few days you are being treated, so wear a bandage over it. -it could also be a chronic skin condition such as eczema or psoriasis, just to name a few, which may require stronger prescription medications for treatment. If it is not improving or if it is getting worse, the best thing to do is to call your doctor for advice. They may want to take a look at the rash in order to diagnose and treat it properly.