BUDAPEST, HUNGARY Mild atopic dermatitis in patients with filaggrin mutations was associated with significantly greater skin barrier dysfunction than in patients with comparable wild-type atopic dermatitis in a comparative laboratory study.
This more pronounced epidermal barrier defect and skin permeability should allow greater penetration of antigenswhich then draw an immune response resulting in contact sensitization and irritancy reactionsas well as predisposition to other atopic diseases such as hay fever and asthma, Dr. Sharizan Abdul-Ghaffar said at the annual meeting of the European Society for Dermatological Research.
This hypothesized chain of events was supported by the findings in the lab study of 13 patients with filaggrin-related atopic dermatitis (AD) and 45 controls with similarly mild AD without filaggrin mutations, according to Dr. Abdul-Ghaffar of the University of Edinburgh (Scotland). The subjects with filaggrin-related AD displayed significantly greater baseline transepidermal water loss on uninvolved flexor forearm skin than did controls. Moreover, the number of tape strips required to mechanically break the skin barrier, as signalled by achieving transepidermal water loss in excess of 20 g/m
A 24-hour application of the irritant sodium lauryl sulfate in various concentrations resulted in dose-dependent increased transepidermal water loss in both patient groups. The increases, however, were consistently greater in the patients with filaggrin mutations.
"This certainly suggests that filaggrin-related eczema patients are less able to cope with irritancy and would explain the increased likelihood of developing problems such as irritant hand dermatitis," she said.
Eleven of the 13 (85%) AD patients with filaggrin mutations had hay fever, compared with 22 of 45 (49%) controls, but the prevalence of asthma in the two groups was similar.
In patch testing using the European Standard Series, 3 of 7 (43%) subjects with filaggrin-related AD developed more than five positive reactions, compared with just 1 of 25 (4%) controls with wild-type AD.
"All of these results certainly support an underlying barrier defect in the pathogenesis of filaggrin-related eczema," concluded Dr. Abdul-Ghaffar.
Several audience members said that they would have expected to see even bigger differences in the test results between AD patients with and without filaggrin mutations.
Dr. Abdul-Ghaffar said the explanation may reside in the selection bias deliberately introduced in the study. Filaggrin-related AD is often at the more severe end of the disease spectrum, but to be eligible for this study patients had to have mild AD.
'This certainly suggests that filaggrin-related eczema patients are less able to cope with irritancy.'
Source DR. ABDUL-GHAFFAR