Suggest Remedy For Random Itchiness On Left Wrist

hi i am experiencing some random itcheness on my left wrist in one particular area that has been persiting for over a day now, there is no evidence of an insect bite or anything like that, the skin in this itchy area looks perfectly normal except for a small red rash that is starting to appear from where i have been occasionally scratching. Any insight into the reasoning of how it has occured would be greatly appreciated. Thank you