Antimicrobial resistance is exceeding stewardship efforts and the rates of new drug development and approval in the market. Dermatologist are among the most common prescribers of oral and topical antibiotics, making antimicrobial resistance a prime concern in daily practice. Through this review of dermatologically relevant pathogens and innovative therapeutics, we hope to further contribute to efforts of bringing the crisis of resistance to the forefront of dermatological practice.

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We summarize the role of blood involvement in mycosis fungoides and Sézary syndrome along with the changes in guideline recommendations for blood involvement assessment. The preferred assessment method is now flow cytometry (FC), and we look at the need for a standardized FC panel and how this might be achieved.

What is already known about this topic?

• Network meta-analyses (NMAs) have become successful in addressing gaps in the comparative effectiveness of the systemic treatments in moderate-to-severe psoriasis.
• Their increasing number carries both a risk of overlap and reproducibility issues that can hamper clinical decision-making.
• Different methodological choices could have an important impact on the results of both classical and network meta-analysis.

What does this study add?

• This overview provides an assessment of the redundancy of the NMAs on the systemic treatments in psoriasis, as well as an evaluation of their methodological quality and discrepancies.
• Of the 47 included studies, only two evaluated all the available treatments, 26 received industry funding and 39 provided results of critically low confidence.
• Awareness is needed among authors and reviewers of the thoroughness of the methods of systematic reviews and meta-analyses.

Linked Comment: J. Leonardi-Bee and A.M. Drucker. Br J Dermatol 2022; 187:3–4.

This article reports the efficacy and safety results from the first chronic hand eczema trial with the topical pan-JAK inhibitor delgocitinib in a cream formulation.

Linked Comment: M.L.A. Schuttelaar. Br J Dermatol 2022; 187:7–8.

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What is already known about this topic?

• Long-term increase in survival from cutaneous malignant melanoma (CMM) is generally attributed to the decreasing trend in tumour thickness, the single most important prognostic factor.
• Targeted therapies and immune checkpoint inhibitors, introduced during the past decade, were shown in phase III trials to improve the prognosis of patients with unresectable and metastatic CMM, but their contribution to the persistent upward trend in overall survival at the population level in Europe is ill-defined.

What does this study add?

• In Italy, the 5-year net survival from CMM in 2013–2017 improved vs. 2003–2007, especially among male patients and in the two highest tumour thickness categories.
• Male patients, for the first time, exhibited the same survival as female patients despite having still thicker lesions. The decrease in median tumour thickness accounted for a small part of the improvement.
• Novel therapies, approved in 2013, are the factor most likely to account for the remaining improvement.

In Italy, the 5-year net survival from melanoma in 2013–2017 improved vs. 2003–2007, especially among male patients and in the two highest tumour thickness categories. Male patients, for the first time, exhibited the same survival as female patients despite having still thicker lesions. The decrease in median tumour thickness accounted for a small part of the improvement. Novel therapies, approved in 2013, are the factor most likely to account for the remaining improvement.

Linked Comment: I.T. Harvima and R.J. Harvima. Br J Dermatol 2022; 187:6–7.

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What is already known about this topic?

• Severe neuropsychiatric outcomes have been reported in individuals exposed to isotretinoin, but the evidence is inconclusive and complicated by several methodological limitations.
• The neuropsychiatric risks potentially associated with isotretinoin treatment are an ongoing concern to clinicians and individuals with treatment-resistant acne.
• Current isotretinoin prescribing guidelines recommend close monitoring for adverse mental health outcomes during isotretinoin treatment.

What does this study add?

• After controlling for various potential sources of bias, isotretinoin was associated with a reduced incidence of adverse psychiatric outcomes (odds ratio 0·80, 95% confidence interval 0·74–0·87) compared with oral antibiotics.
• Isotretinoin appeared to reduce the excess psychiatric risk associated with treatment-resistant moderate-to-severe acne.
• In monitoring potential adverse outcomes during isotretinoin treatment, clinicians should also consider the high mental health burden associated with treatment-resistant acne and the potential contribution of physical side-effects of the prescribed medication on mental health.

In this propensity score matched cohort study of electronic medical records, we found that after controlling for various potential sources of bias, isotretinoin was associated with a reduced incidence of adverse psychiatric outcomes (odds ratio 0.80, 95% confidence interval 0.74–0.87) when compared to oral antibiotics. Isotretinoin thus appeared to reduce the excess psychiatric risk associated with treatment-resistant moderate-to-severe acne.

Linked Comment: J. Ravencroft and L. Eichenfield. Br J Dermatol 2022; 187:8–9.

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What is already known about this topic?

• Alopecia areata is a common cause of nonscarring hair loss.
• Psychological comorbidity is common in people with alopecia areata, but limited information is available on the co-occurrence and impact of depression and anxiety in this group.

What does this study add?

• Adults newly diagnosed with alopecia areata (5435 in UK primary care) have a higher background prevalence of depression and anxiety than population controls, and are also at 30–38% higher risk of being subsequently diagnosed with new-onset depression and anxiety.
• After alopecia areata diagnosis, people with the condition are more likely to be issued time off work certificates (56% higher) and to be recorded as unemployed (82% higher risk) than population controls.

Adults newly diagnosed with alopecia areata (n=5435 in UK primary care) have a higher background prevalence of depression and anxiety than population controls. After diagnosis they are additionally had a 30–38% higher risk of being diagnosed with new onset depression and anxiety after diagnosis and are more likely to be issued time-off work certificates (56% higher) and be recorded as unemployed (82% higher risk), than population controls.

Linked Comment: N. Hunt. Br J Dermatol 2022; 187:9–10.

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Shotgun metagenomic sequencing analysis demonstrated a dysbiotic taxonomic and functional gut microbiota in psoriasis cases when compared with age, sex and BMI matched healthy controls. In addition, the gut microbiota discriminates patients with psoriasis from their healthy partners

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What is already known about this topic?

• At present, there is no standard nomenclature for describing the spectrum of constitutive skin colour across human populations.
• The Fitzpatrick scale of skin phototypes was developed as a simple method for describing the sun reactivity of human skin.
• The widespread and incorrect use of the Fitzpatrick scale to describe skin colour has led to a systematic lack of recognition of the diversity of darker skin colours.

What does this study add?

• The Eumelanin Human Skin Colour Scale is a five-point scale that describes the full spectrum of human constitutive skin colour.
• Eumelanin, the dominant chromophore of human skin, is a central descriptive word in the nomenclature of the scale.
• The scale is referenced on published skin reflectance data.

The Eumelanin Human Skin Colour Scale and how it correlates to the diversity of human skin pigmentation across human populations.#10.

What is already known about this topic?

• Melanoma and keratinocyte skin cancers have a significant impact on population health and healthcare budgets, and a proportion are attributable to indoor tanning.
• Policy-based interventions that restrict or ban the commercial provision of indoor tanning are in place around the world to reduce the burden of skin cancer, but economic evidence to support decision making is lacking.

What does this study add?

• Banning indoor tanning, supported by a public health campaign, would be an efficient use of healthcare resources to reduce melanoma and keratinocyte cancers in England.
• This policy-intervention would save lives (4.6% melanoma deaths avoided) and reduce skin cancer treatment costs with a high degree of confidence.
• The structured and transparent analysis means that decision makers in other jurisdictions can assess the relevance of these findings to their context.

The use of indoor tanning devices causes harm to individuals and increases healthcare costs. A model-based cost-effectiveness anlaysis was used to estimate the economic impact of a policy-based intervention to reduce skin cancers associated with indoor tanning. Implementation of the intervention across England would realise health gains and reduce healthcare costs.

Linked Comment: M. Janda and C. Sinclair. Br J Dermatol 2022; 187:7.

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Enfortumab vedotin (EV), a novel antibody-drug conjugate approved for metastatic urothelial carcinoma, causes a variety of cutaneous adverse reactions. We present two cases of bullous eruptions following treatment with EV, both demonstrating IgG deposition on direct immunofluorescence (DIF) correlating to the location of nectin-4 in the epidermis. This suggests that the IgG component of EV binding to nectin-4 in keratinocytes is likely a primary contributor to the high rates of cutaneous toxicity.