Pseudoephedrine Hydrochloride and rash

I first took Pseudoephedrine HCl over 30 years ago while in the USAF, under the brand name Actifed, which at the time was prescription only. Within a day or so, I began to notice a blood-red rash starting to appear on areas of my body not exposed to light. Perhaps the areas were also the warmest areas. I returned to the doctor and was advised to stop taking the drug. Many years later, Sudafed was released as an OTC medication and when I tried it, the rash returned. It took a bit to determine the culprit was the Pseudoephedrine, but since then, I have avoided any medications with it as the active ingredient. The worst part is that the medication is otherwise extemely effective.