How Can Allergic Rashes On The Forehead Be Treated?

There is a spot on my forehead that has become a reoccurring issue over the passed 15 years or so. About once or twice a year, when I m exposed to extreme heat/sweat, it flares up. I was in FL this passed weekend and spent a great deal of time outside so naturally it was exposed to heat/sun and by proxy, sweat. In the past I ve tried to treat it with Triamcinolone Acetonide Cream (.1%) which has seemed to help somewhat, but not very efficiently. The rash appears as clusters of tiny little red bumps and tends to expand. They are filled with a clear liquid and are very itchy. Often times the bumps will pop and eventually scab over which leaves me with a sizable scab on my forehead for some time. I m looking for a more effective way to treat it. I ve been to the doctor a few times to try to determine what it is, but I haven t had much success.