The problem with irritant contact dermatitis is that it is almost never the
result of contact with a single substance. It is the result of repeated
insults to the skin from contact with many different irritants. Over time
the damage from each contact accumulates until the skin finally succumbs.
There is no recognised technique for diagnosing irritant contact dermatitis
other than eliminating allergic reactions, taking a detailed history and
from this formulating an opinion. Considering that there are many irritants
away from the workplace and that we spend less time at work than we do away
from work, determining whether a dermatitis is occupational in nature is
often fraught with difficulty. Indeed, I use the definition of occupational
dermatitis: "A clinically recognisable contact dermatitis caused entirely or
substantially due to workplace exposure" as we can never be absolutely
certain that we have identified and incorporated all non-occupational
factors into the investigation.
In several instances I have investigated a case of dermatitis that has been
diagnosed as occupational, sometimes having involved patch testing in the
diagnosis, to conclude that this was not, after all, occupational. It is a
complex process involving identifying workplace exposure and to what,
assessing how the clinical diagnosis was made, and identifying
non-occupational and other factors. The conclusion can differ from the
clinical diagnosis, if only because the dermatologist was not aware of some
of the workplace factors and did not thus include them when carrying out the
patch test on which the diagnosis was based. It is far more complex than
many realise. All sorts of different elements can be important, including
psychosomatic conditions.
Incidentally, to amplify Anne's comment we need to differentiate between
sensitisation and allergy. Sensitisation is the process by which the immune
system becomes capable of developing an allergic response. It is perfectly
possible to be sensitised but not allergic. Moreover, patch testing only
determines sensitisation to a given substance, not necessarily that the is
the cause of an allergic response. That involves other elements of the
investigation.
However, the fact remains that once a registered medical practitioner has
diagnosed an occupational dermatitis it is reportable. My policy is that
until that happens reporting is more likely to obstruct a proper
investigation than not as once others, perhaps with less in depth knowledge
of this complex topic, become involved it can be more difficult to come to
the correct conclusion, without which it is very difficult to properly
manage the situation so as to keep that person at work with a healthy skin.
Chris
Chris Packham
FRSPH, FInstSMM, MCMI, MIIRSM, MBICSc
EnviroDerm Services
Unit 10, Building 11, The Mews, Mitcheldean, GL17 0SN
Tel: +44 1386 832 311 (office), Mobile: +44 7818 035 898
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