Clinical features and biomarker differences of severe intrinsic and extrinsic atopic dermatitis

ObjectivesAtopic dermatitis (AD) can be classified into intrinsic AD(IAD) and extrinsic AD(EAD). However, the differences in clinical features and pathogenesis between these two subtypes of AD are currently unclear. This study aimed to analyse the differences in clinical features and peripheral blood biomarkers between Chinese patients with severe IAD and EAD in order to elucidate the physiopathogenesis of AD.Materials and methodsA total of 316 hospitalised patients definitively diagnosed with severe AD were included in this study. There were 72 cases of severe IAD and 244 cases of severe EAD. The clinical features of the patients were recorded in details. Serum total IgE, IgA, IgG, IgM, complementC3/C4, peripheral blood cell counts, lactate dehydrogenase (LDH), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), IL-2R, IL-6, IL-8, and TNF-alpha in AD patients and 60 age-matched healthy controls were analysed. IAD and EAD had similar severity/Scoring Atopic Dermatitis (SCORAD) scores.ResultsCompared with healthy controls, IAD patients had significantly higher total IgE, eosinophils, monocytes, LDH, CRP, IL-2R, IL-6, IL-8 and TNF-alpha, and lower IgM and C4. EAD patients had significantly higher total IgE, IgA, eosinophils, white blood cell (WBC) counts, neutrophils, monocytes, basophils, LDH, CRP, IL-2R, IL-6, IL-8, TNF-alpha and lower IgM than healthy controls. IAD patients had a higher percentage of rural/urban living and female/male, a shorter course of disease and lower total IgE, eosinophils, WBC counts, neutrophils, monocytes, basophils, LDH, IgG and C4 than EAD patients. SCORAD scores, eosinophils, LDH expression levels increased with total IgE uniquely in patients with EAD.ConclusionsIAD and EAD exhibit specific clinical features and molecular changes. IAD has a more complex physiopathogenesis, and deserves further investigation.