When you have seborrheic dermatitis does it mean something is seriously wrong with your body? Or it's not as serious as it feels?

It's trivial. Hi Meghan -- seborrheic dermatitis is a trivial process kept going by a curious relationship between your body chemistry and a particular tiny fungus. Anyone who tells you that common seborrhea (as opposed to the very severe form that can be seen in AIDS) means your seriously sick is feeding your disinformation. Take charge and start managing your skin scientifically. You deserve to be healthy.