Background:
Aeroallergens from
house dust mite (HDM)
may be an important
trigger in a
subgroup of patients
with atopic
dermatitis (AD). HDM
and cockroach (CR)
contain
cross-reactive
allergens, such as
tropomyosin.
Objective: To
investigate the
diagnostic value of
patch testing with
an aeroallergen and
the role of CR
allergen and HDM
allergen in persons
with AD.
Methods: We
performed skin prick
tests (SPT) with a
panel of common
aeroallergens and
total serum
immunoglobulin (Ig)E
and specific IgE
tests for CR and HDM
on 23 patients with
AD and 9 nonatopic
control
participants. Atopy
patch tests (APT)
were performed with
CR and HDM extracts
on clinically
uninvolved skin on
the back, and
evaluated after 48
and 72 hours.
Results: A
positive APT
reaction to CR was
found in 10/23 (43%)
patients with AD. No
positive reactions
were observed in the
nonatopic control
participants.
Positive APT
reactions for CR
showed no
significant
correlation with SPT
or specific IgE
levels for this
allergen. Twelve of
the 23 (52%)
patients with AD
were also sensitized
to HDM. There was no
significant
correlation between
positive results for
SPT, APT, and
specific IgE to CR
and HDM.
Conclusion:
We demonstrate that
CR allergens can
induce positive
patch test reactions
in patients with AD.
The absence of a
significant
correlation to SPT
and specific IgE
antibodies suggests
that T-cell- and IgE-sensitization
may be mediated by
different allergens.
There was no
significant
relationship between
CR and HDM
sensitivity, thus
indicating no major
cross-reactivity.
Key words:
Atopic dermatitis.
Atopy patch test.
Cockroach.
Cross-reactivity to
house dust mit
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