Every now and then my beard and sideburns get really dry and itchy and red, do you any long term remedies besides scratching it?
Stubble and beards are infamous for irritating sensitive skin. Are you currently using any moisturizers on that area?
Not at the moment, I try to avid using harsh shampoos on my face and use face cleanser for sensitive skin.
Then I would definitely start using a moisturizer daily. If you don't normally deal with dry or irritated skin, then I would probably start with something simple. Whichever low fragrant lotions you have around the house, particularly something will aloe should be fine. Apply it at least every morning and night, but a third time midday wouldn't hurt if you are feeling itchy at that time.
I have issues with the skin under my beard getting dry and flaky, so I moisturize regularly, and I use Selsun Blue once or twice a week to reduce flaking.
I don't have a beard or even stubble yet. I use an oil free lotion on my face because it kept getting really dry. It has helped a ton.
This is why I started trimming my beard. Usually it's worse when you've just started growing a beard and have all these little hairs piercing the skin because they may have been covered over if the shaving was not clean enough or later on when they get longer and curl back onto the skin surface.