Is eczema the same as dermatitis?

Yes, and no!
‘Dermatitis’ is a more generalised word, simply meaning
inflammation of the skin. All eczema is dermatitis, but many other
conditions that can be called dermatitis fall within the grouping of
dermatitis. Most of the different types of eczema can, and often
are, interchangeably termed dermatitis – the term is more
commonly used in the USA. Previously more than now, an
eczematous process caused by an irritant or allergic problem in
the workplace was called contact dermatitis, and issues concerning
compensation might at least have been implied.
For some types of eczema, it is more commonplace to use
‘dermatitis’. Cases include napkin (diaper) dermatitis, photo-
dermatitis and neuro-dermatitis. For others, for example asteatotic
eczema, ‘eczema’ has been the preferred term. For some of the rest
– such as seborrhoeic and discoid – eczema and dermatitis are used
interchangeably. The situation is therefore still very confusing, and
it is always worth asking your doctor if he or she means something
different from your understanding of the words.