C. Gutgesell et al., Inverse correlation of domestic exposure to Dermatophagoides pteronyssinusantigen patch test reactivity in patients with atopic dermatitis, CLIN EXP AL, 29(7), 1999, pp. 920-925
Background In recent years considerable interest in the pathogenetic role o
f aeroallergens exacerbating atopic dermatitis (AD) has emerged. The 'atopy
patch test' with aeroallergens was introduced by Platts-Mills et nl. as an
experimental model and as a diagnostic tool. However, its relevance for th
e clinical manifestation of AD is still not clear.
Objective We asked whether there is a relationship between the individual a
ntigen exposure to the major allergen of Dermatophagoides pteronyssinus (De
r p 1) and the immunological markers of sensitization to Der p I or the cli
nical severity of AD.
Methods We investigated 92 patients with moderate to severe AD. For clinica
l evaluation the SCORAD severity score was used. Patch tests were performed
with purified Der p 1. Specific IgE was measured by a commercial assay. De
r p 1 exposure was quantified in a sample of the patient's mattress dust by
using a commercial ELISA.
Results No correlation between SCORAD, Der p 1 exposure and PAST could be e
stablished. However, there was an unexpected significant inverse correlatio
n between the quantity of mite antigen in the mattress dust and patch test
reactivity. Patients with a high antigen load (> 25 mu g/g) mostly had a ne
gative patch test. Also, when Der p 1 was correlated to the mattress area (
m(2)) in this group all patch tests were negative. A possible explanation c
ould be that continuous exposure of the skin to house dust mite allergen De
r p 1 may induce a down-regulation of the skin immune system of patients wi
th AD.
Conclusion Although the mechanism of this phenomenon is presently unknown,
our study shows that a positive allergen patch test alone should not be an
indication to undertake allergen exclusion measures in AD patients.