Environmental Engineering Reference
In-Depth Information
erythematosus (SLE) (Parks et al. 2011). However, this effect seems to depend on the type of
pesticide, as the risk for developing autoantibodies shows a positive correlation with occu-
pational exposure to trifluralin, but a negative correlation with exposure to bromoxynil
and 2,4-dichlorophenoxyacetic acid (Semchuk et al. 2007). Bisphenol-methoxychlor stimu-
lates the human keratinocytes to express the SS-A/Ro autoantigens that are associated
with SLE, Sjögren's syndrome, and other autoimmune connective tissue diseases with
prominent skin involvement (Sakabe et al. 1998).
16.5 Pesticide-Related Skin Diseases
Pesticides form a very heterogeneous group of substances that are classified according
to utilitarian criteria; therefore, their chemical structures and biological effects are very
diverse. An apparently common feature of these substances is their high biological activ-
ity, which may affect also the human skin. An overview of pesticide-related skin disorders
is given in Table 16.1 .
16.5.1  Chemical Burns
Skin contact with corrosive chemicals may cause direct destruction (necrosis) of the
exposed tissues. As corrosive properties of the chemicals become apparent at an early
stage of the safety assessment, skin burns are mainly the results of accidental exposures to
concentrated pesticides, their criminal (homicidal or suicidal) use, or extremely negligent
handling.
16.5.2  Irritant Contact Dermatitis
Irritant contact dermatitis (ICD) is among the most frequent occupational diseases world-
wide. Its clinical diagnosis is relatively difficult to establish with an undisputed certainty,
mainly due to the following factors: (1) Similarity of symptoms and frequent overlapping
with ACD; (2) On individual basis, there is little possibility of confirming the causal link
between the disease and a particular exposure; and, most importantly, (3) The diagnosis of
“irritant contact dermatitis” is made by exclusion: there is no other way of establishing the
diagnosis of ICD than by excluding all other types of dermatitis. Altogether, this leads to a
considerable underreporting of ICD, both at the individual and population levels (Spiewak
2003). Table 16.2 presents a proposal of working criteria for the diagnosis of work-related
ICD, which are a compilation of own experience (Spiewak 1999) and criteria proposed by
Penagos (2002).
16.5.3  Phototoxic Contact Dermatitis
The terms “phototoxic reaction” and “phototoxicity” refer to an inflammatory reaction of
the skin, resulting from direct cellular damage produced by the photochemical reaction
initiated by photoactive chemicals (photosensitizers) and the active spectrum of radiation
on the skin, mainly in the UVA range (Spiewak 2009b). The two main pathways of photo-
toxicity are reactive oxygen species (ROS) pathway and reactive nitrogen species (RNS)
pathway. The most common clinical manifestation of phototoxicity is an exaggerated,
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