What causes eczema?

Introduction
It must be very frustrating to ask your doctor why you have eczema
only to get a vague answer suggesting several possible causes. The
truth is that we don’t yet have a simple answer to this simple
question – and we may never have. In this chapter we will try to
explain what our current understanding is and, just as importantly,
try to dispel some of the myths that abound. It may be easier to
establish what does not cause eczema, but we fully understand
that myths and untruths will arise if we do not fully understand the
causes of eczema. It is important to do clear up misconceptions of
the cause as they can lead to wholly inappropriate treatment and
poorly controlled disease. If there were a simple answer to ‘What
causes eczema?’, you would not be reading this book! As with much of this book, we have many more answers related
to studies on atopic eczema and contact eczema than on some of
the other types, but the general messages are appropriate for all
the different types.
Are there any common things that make eczema worse?
This depends to some extent on what type of eczema you are talking
about. Much more research has been carried out in people with
atopic eczema, so most of the answers to the more general questions
relate more to atopic eczema than to the other forms. It is safe to
say that if you have large areas of contact eczema, your skin is likely
to be irritated by the same sorts of thing that have come up in studies
of atopic individuals. Apart from the use of soaps and other things
that can directly irritate the skin, the most common reasons are
sweating (usually from exercise), fabrics (especially if the contact
was at work) and hot weather. Fabrics encountered at work seem
to relate not just to a direct irritant effect, but also to a physical
friction effect if they have to be handled constantly as part of a job.