What's already known about this topic?

• Atopic dermatitis is a common and highly debilitating chronic inflammatory skin disorder.
• Immune dysregulation plays a key role, but recent evidence has shifted the focus to skin barrier disruption as the key precursor.
• Loss-of-function mutations in the filaggrin gene are the strongest known genetic risk factor, but there are numerous environmental and immunological factors that influence the disease manifestation and course.
• The current therapeutic armamentarium is limited to simple lipid-based barrier-enhancing emollients, topical anti-inflammatory agents and systemic immunosuppressive therapies.

What does this study add?

• We review how defects in structural epidermal proteins and environmental factors converge to impair skin barrier function, resulting in increased susceptibility to atopic dermatitis.
• We explore the impact of the defective skin barrier on immune responses and the skin microbiome, highlighting how the complex interplay between the skin barrier and immune activation determines the response to environmental factors such as allergens and microbes.
• We outline emerging strategies for treating and preventing atopic dermatitis.

Linked Comment: Silverberg. Br J Dermatol 2019; 180:447–448.

What's already known about this topic?

• Optical coherence tomography (OCT) is a noninvasive imaging modality that can be used to diagnose basal cell carcinoma (BCC).
• Morphological features found on OCT images correlate with specific histopathological findings.
• OCT can also detect subclinical extension of tumours and improve preoperative delineation of surgical margins.

What does this study add?

• This study analysed tumour-level data from 31 published studies encompassing 901 BCCs.
• We calculated the diagnostic sensitivity and specificity of different OCT systems, determined the degree of correlation between OCT morphological features and BCC diagnosis and analysed tumour and machine factors that affect OCT estimation of tumour depth.

Linked Comment: Navarrete-Dechent et al. Br J Dermatol 2019; 180:448–449.

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What's already known about this topic?

• Various symptomatic treatment options exist for congenital ichthyoses, but there are no European guidelines.

What does this study add?

• These European guidelines for the management of congenital ichthyosis may help to improve outcomes and quality of life for patients.

Linked Comment: Akiyama. Br J Dermatol 2019; 180:449–450.

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Linked Editorial: Wang and Bagot. Br J Dermatol 2019; 180:443–444.

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Linked Editorial: Gran. Br J Dermatol 2019; 180:445–446.

What's already known about this topic?

• Patients with cerebrovascular or neurological diseases (e.g. dementia, Parkinson disease) have a higher risk of bullous pemphigoid (BP) development.
• Whether cancer is a risk factor for BP remains controversial.

What does this study add?

• In this population-based study, there was no increased risk for BP in patients with cancer.
• Age, diabetes mellitus and cerebrovascular disease were independent risk factors for BP.

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Linked Comment: Hammers and König. Br J Dermatol 2019; 180:451–452.

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What's already known about this topic?

• Atopic dermatitis can influence quality of life, but little is known about its possible impact on educational attainment.

What does this study add?

• Atopic dermatitis was not associated with lower cognitive function or poorer academic attainment in this large general-population-based cohort study of men in Sweden.
• Men with atopic dermatitis had lower stress resilience in late adolescence, which has potential adverse implications for mental and physical health in subsequent adulthood.

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Linked Comment: Vittrup and Thyssen. Br J Dermatol 2019; 180: 452–453.

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What's already known about this topic?

• Cutaneous adnexal carcinomas (CACs) are rare tumours, but their incidence is increasing.
• The rarity of these tumours has made it difficult to gain sufficient clinicopathological experience regarding the diagnosis and treatment of CACs.
• CACs can be a diagnostic challenge owing to mostly nonspecific clinical presentation and histopathological variety that often requires specific expertise for a definite diagnosis.

What does this study add?

• CAC incidence increased from 2·5 per million person-years in 1985–87 to 19 per million person-years in 2009–10; from 1997 the incidence has constantly increased, rising to 159% in 2010.
• In patients with CAC, the risk of squamous cell carcinoma is 34 times higher than in the general population.
• Considering demographic evolution with a progressively ageing population and higher incidence of CACs among the elderly, it is reasonable to expect a further increase in the future.

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Linked Comment: Andersen. Br J Dermatol 2019; 180:453–454.

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What's already known about this topic?

• There are no firm clinical recommendations for the treatment of vitiligo.
• One of the main issues is the heterogeneity of outcome measures used in randomized controlled trials for vitiligo.

What does this study add?

• Based on international consensus and the best available evidence, repigmentation should be assessed by measuring the percentage of repigmentation in quartiles (0–25%, 26–50%, 51–79%, 80–100%).
• The cosmetic acceptability of results should also be assessed, for example using the Vitiligo Noticeability Scale.

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Linked Comment: Wolkerstorfer. Br J Dermatol 2019; 180:454–455.

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What's already known about this topic?

• The Vitiligo Impact Scale (VIS)-22 is a quality-of-life instrument tailored specifically to the needs of patients with vitiligo.
• Criterion, convergent and known-groups validity, and the reliability and responsiveness of VIS-22 have been studied previously in Indian patients.
• VIS-22 scores range from 0 to 66. The clinical meaning of VIS-22 scores has not been studied before.

What does this study add?

• The clinical meaning of VIS-22 scores is assigned as follows: 0–5, no effect; 6–15, mild effect; 16–25, moderate effect; 26–40, large effect and 41–66, very large effect on quality of life.
• VIS-22 performed better than the Dermatology Life Quality Index in evaluating the quality of life of patients with vitiligo.

What are the clinical implications of this work?

• Clinicians can use VIS-22 to measure the degree of impact on the life of patients with vitiligo and to tailor treatment strategies accordingly.

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What's already known about this topic?

• Atopic dermatitis is a clinically heterogeneous condition with multiple clinical manifestations and a complex pathogenesis.
• Systemic biomarkers of severity have been identified in adults, but are less well defined in children.
• Biomarkers from the skin compartment have been based on biopsies to date.

What does this study add?

• Noninvasive sampling can detect clinically relevant biomarkers in AD skin.
• These biomarkers may be useful for disease stratification, and provide insights into the pathogenesis of infant AD.
• Innate immune activation is important in the epidermis in infantile AD.

What is the translational message?

• Noninvasive biomarkers can yield significant insights into infantile AD.
• They identify innate activation, the T helper 2 pathway and angiogenesis as important pathways in this condition.

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Linked Comment: Hijnen. Br J Dermatol 2019; 180:455–456.

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What's already known about this topic?

• Excessive exposure to ultraviolet (UV) radiation can lead to increased production of free radicals and hence to skin damage such as inflammation, premature skin ageing and tumour progression.
• The visible and near infrared (NIR) regions of the solar spectrum also induce radicals.
• Half of all free radicals in skin types I–III are due to visible + NIR exposure, but data about the effects in skin types IV–VI are missing.

What does this study add?

• This in vivo pilot study addresses the distribution of radical production in skin types IV and V during irradiation in the UV, visible and NIR spectral regions, comparing the results with those of skin type II.
• The results provide the first ideas of possible long-term effects of excessive exposure to visible and NIR radiation in skin types IV and V.

What is the translational message?

• In people with skin types IV–V, significantly more radicals were formed during NIR irradiation compared with skin type II.
• As in skin types IV–V the NIR values reach or exceed those of the UV and visible, which could influence premature skin ageing and carcinogenesis.
• Individuals with skin types IV–VI might need a different type of sun protection from those with skin types I–III to avoid subsequent damage by solar radiation.

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Linked Comment: Young. Br J Dermatol 2019; 180:456–457.

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What's already known about this topic?

• Sun protection factors (SPFs) are determined with sunscreen application at 2 mg cm⁻², but people typically use much less.
• Suboptimal sunscreen application is often associated with sunburn, which is a risk factor for skin cancer.
• Erythema is a biomarker of cyclobutane pyrimidine dimers (CPDs), which may initiate skin cancer.
• The suppression of the sensitization phase of the contact hypersensitivity (CHS) response is a model for photoimmunological events in skin cancer.

What does this study add?

• Typical sunscreen use during a week's holiday in Tenerife, with a very high UV index, resulted in erythema, epidermal CPD formation and almost complete suppression of CHS.
• There was no erythema, on five exposed body sites, when sunscreen (SPF 15) was applied three times daily at ≥ 2 mg cm⁻².
• Erythema is predictive of immunosuppression, irrespectively of the ultraviolet radiation (UVR) emission spectrum.

What is the translational message?

• People can learn to use sunscreens correctly to achieve the labelled SPF.
• The laboratory study demonstrated that erythema is a clinical and spectral biomarker for UVR-induced suppression of CHS.
• Prevention of holiday erythema is likely to reduce CPDs and photoimmunosuppression, which are critical risk factors for skin cancer.
• Avoidance of erythema is therefore a very important public health strategy.

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Linked Comment: Hart. Br J Dermatol 2019; 180:462–463.

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What's already known about this topic?

• Pyoderma gangrenosum (PG) represents a diagnosis of exclusion.
• Objective and systematically evaluated diagnostic approaches for patients with suspected PG are lacking.

What does this study add?

• A comprehensive and practicable diagnostic scoring system for PG was developed and evaluated by expert teams at two leading tertiary dermatological centres specializing in wound care. The initial letters of the score criteria form the acronym PARACELSUS.
• A total score of 10 points or higher indicates a high likelihood of PG and differentiates PG from venous leg ulcers.
• The PARACELSUS score is an effective and easily implementable diagnostic tool for PG.

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Linked Editorial: Schreml. Br J Dermatol 2019; 180:438–439.

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What's already known about this topic?

• Atopic dermatitis (AD) affects children of all skin types, but most research is focused on white people with light skin types.
• Studies investigating biomarkers in patients with AD with dark skin types are lacking.
• Tape-stripping can be used for analysis of skin barrier and immune response biomarkers in AD skin.

What does this study add?

• Stratum corneum tape-stripping is suitable to study a broad panel of biomarkers in children with AD.
• We show differences in skin barrier and immune response biomarkers between lesional, nonlesional and control skin.
• Immune response biomarkers are similar in light and dark skin types. However, natural moisturizing factor levels differ between skin types II and VI, suggesting a different pathogenesis in AD between light and dark skin types.

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Linked Comment: Furue. Br J Dermatol 2019; 180:457–458.

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What's already known about this topic?

• The determination of causative organisms of onychomycosis is still not optimal.
• There remains a need for a cheap, fast and easy-to-perform diagnostic tool with a high capacity to distinguish between organisms.

What does this study add?

• Attenuated total-reflectance Fourier transform infrared spectroscopy is a potential novel tool in the detection and differentiation of causative organisms of onychomycosis.

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Linked Comment: Kumar. Br J Dermatol 2019; 180:459–460.

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