Atopic dermatitis (AD) is a chronic, recurrent inflammatory skin disease with a wide range of heterogeneity. Accurate biomarkers or predictors are the keys to instructing personalized tailored precise treatment. The development of technology such as transcriptomics, genomics, and proteomics provides novel insights into the possibility to find potential biomarkers. Meanwhile, emerging minimally invasive methods such as tape stripping were used to reveal different profiles of patients’ skin without biopsy. Several potential biomarkers or predictors have been found. In this review, we summarized the current development of potential biomarkers of AD. Nitric oxide synthase 2/inducible nitric oxide synthase (NOS2/iNOS), human beta-defensin-2 (hBD-2), and matrix metalloproteinases 8/9 (MMP8/9) may be the candidate biomarkers for AD diagnosis. Filaggrin (FLG) gene mutation increased the occurrence risk of AD. Fatty-acid-binding protein 5 (FABP5) may serve as an effective biomarker for the atopic march (AM). Squamous cell carcinoma antigen 2 (SCCA2), serum thymus and activation-regulated chemokine (TARC), cutaneous T-cell-attracting chemokine (CTACK), eosinophil-derived neurotoxin (EDN), macrophage-derived chemokine (MDC), lactate dehydrogenase (LDH), and interleukin (IL)-18 can be the candidate biomarkers for disease severity monitoring. IL-17, IL-23, IL-33, and indoleamine 2,3-dioxygenase (IDO1) can be used as predictive biomarkers for AD comorbidities. LDH, TARC, pulmonary and activation-regulated chemokine (PARC), periostin, IL-22, eotaxin-1/3, and IL-8 may be the candidate biomarkers for monitoring treatment effects. There are still unmet needs and a long way to go for more convenient, non-invasive, and effective predictors and biomarkers to better guide personalized precise treatment.

Atopic dermatitis (AD) is a chronic and recurrent inflammatory skin disease, affecting up to 10% to 20% of children and 3% of adults. Although allergen sensitization, skin barrier abnormalities and type 2 immune responses are involved, the exact molecular pathogenesis of AD remains unclear. MicroRNAs (miRNAs) are short (19‐25 nucleotides) single‐stranded RNA molecules that regulate gene expression at post‐transcriptional level and are implicated in the pathogenesis of many inflammatory and immunological skin disorders. This systematic review sought to summarize our current understanding regarding the role of miRNAs in AD development. We searched articles indexed in PubMed (MEDLINE) and Web of Science databases using Medical Subject Heading (MeSH) or Title/Abstract words (‘microRNA/miRNA’ and ‘atopic dermatitis/eczema’) from inception through January 2020. Observational studies revealed dysregulation of miRNAs, including miR‐143, miR‐146a, miR‐151a, miR‐155 and miR‐223, in AD patients. Experimental studies confirmed their functions in regulating keratinocyte proliferation/apoptosis, cytokine signalling and nuclear factor‐κB‐dependent inflammatory responses, together with T helper 17 and regulatory T cell activities. Altogether, this systematic review brings together contemporary findings on how deregulation of miRNAs contributes to AD.

The prevalence of atopic dermatitis (AD) has increased substantially. Previous studies have focused mostly on pediatric patients, while epidemiological investigation on adult AD has been very limited. The aim of this study was to determine the prevalence and clinical features of adult AD in outpatients with dermatitis and eczema in China mainland. A multicenter cross-sectional study was conducted among outpatients with eczema or dermatitis from 39 tertiary hospitals of 15 provinces in China from July 1 to September 30, 2014. Of 8758 patients, 407 were adult AD. Compared with adults with other types of dermatitis, the mean age (41.8 ± 14.3 vs 42.04 ± 15.38 years, P < 0.05) and onset age (35.2 ± 11.2 vs 39.2 ± 14.0 years, P < 0.001) of adult AD were younger, and mean disease duration was longer (5.3 ± 7.1 vs 2.8 ± 4.9 years, P < 0.001). About 53.3% adult AD involved 3 or more body locations, higher than adults with other types of dermatitis (34.4%, P < 0.001), but lower than those with pediatric and adolescent AD (73.8%, P < 0.001). History of asthma (19.2% vs 6.9%, P < 0.001) or allergic conjunctivitis (21.9% vs 14.9%, P < 0.05) was more common in adult AD than pediatric/adolescent AD. Suspected bacterial infection was more frequently in adult AD than adults with other types of dermatitis (24.3% vs 14.6%, P < 0.001) and pediatric/adolescent AD (24.3% vs 14.9%, P < 0.001). More severe itching was observed in 31.4% of adult AD, higher than that of adults with other types of dermatitis (15.4%, P < 0.001), whereas similar to that of pediatric/adolescent AD (28.7%, P > 0.05). The highest (8.7%) and lowest prevalence (3.7%) of adult AD were in 25°N to 30°N and 35°N to 40°N latitude region. A substantial part of adult outpatients with eczema or dermatitis is adult AD. Middle age, more body location involvement, more suspected bacterial infection, and severe itching are the main clinical feathers of adult AD. Geographical environment and economic situation work in synergy to adult AD.