Actinic keratosis (AK) is a lesion that arises as a result of excessive exposure to solar radiation and appearing predominantly on Fitzpatrick phototype I and II skin. Given that some AKs evolve into squamous cell carcinoma, these lesions are considered premalignant in nature, occurring mostly in elderly men and immunosuppressed individuals chronically exposed to ultraviolet (UV) radiation. There are several mechanisms for the formation of AKs; among them are oxidative stress, immunosuppression, inflammation, altered proliferation and dysregulation of cell growth, impaired apoptosis, mutagenesis, and human papillomavirus (HPV). Through the understanding of these mechanisms, several treatments have emerged. Among the options for AK treatment, the most commonly used include 5-fluorouracil (5-FU), cryotherapy, diclofenac, photodynamic therapy (PDT), imiquimod (IQ), retinoids, and ingenol mebutate (IM). There have been recent advances in the treatment options that have seen the emergent use of newer agents such as resiquimod, betulinic acid, piroxicam, and dobesilate. The combination between therapies has presented relevant results with intention to reduce duration of therapy and side effects. All AK cases must be treated because of their propensity to transform into malignancy and further complicate treatment. In addition to medical or surgical care, education about sun exposure prevention remains the best and most cost-effective method for AK prevention. The objective of this article is to conduct a literature review of the clinical presentation of AK including advances in treatment options available.

Background Acanthosis nigricans (AN) is a cutaneous disorder characterized by symmetric velvety hyperpigmented plaques on intertriginous areas like axilla, neck, inframammary, and groin. Aims To summarize the pathophysiology and classification of AN, provide an update of diagnostic testing strategies, and describe the current therapeutic options described so far in the literature for this disease. Methods A comprehensive english language literature search across multiple databases (PubMed, EMBASE, MEDLINE, and Cochrane) for keywords (alone and in combination) was performed. MeSH as well as non‐MeSH terms such as “acanthosis nigricans,” “classification,” “pathophysiology,” “diagnosis,” “treatment,” “topical drugs,” “systemic drugs,” “chemical peeling,” and “lasers” were taken into consideration. Results The pathophysiology of AN revolves around a multifactorial stimulation of proliferation of epidermal keratinocytes and dermal fibroblasts. Various types of AN include benign, obesity‐associated, syndromic, malignant, acral, unilateral, medication‐induced, and mixed‐type. Homeostasis model assessment‐insulin resistance (HOMA‐IR) is a good tool for assessment of insulin resistance. Management involves general measures (weight reduction and addressing the underlying cause, if any), topical drugs (retinoids, vitamin D analogs, and keratolytics), oral drugs (retinoids and insulin sensitizers), chemical peels (trichloroacetic acid), and lasers (Long pulsed alexandrite, fractional 1550‐nm erbium fiber, and CO2). Conclusion Acanthosis nigricans is a treatable condition; however, complete cure and disappearance of lesions are difficult to achieve. Weight reduction is the most scientific and practical management strategy. Long‐term studies and further research is warranted in the pathophysiology and treatment of this common condition.

Background Psoriasis is a common disease that has not only cutaneous manifestations but also causes significant systemic illness and disability. Most epidemiological studies on the burden of psoriasis that are available in literature are regional, and thus a detailed description of the worldwide burden of psoriasis is warranted.Methods We analyzed the prevalence, incidence, disability adjusted life years (DALY), and years lived with disability (YLD) related to psoriasis for the period 1990 to 2017, from the Global Burden of Disease dataset (developed by the Institute of Health Metrics, University of Washington). We also searched the PubMed MEDLINE for quality of life and economic burden of psoriasis for a comprehensive evaluation of the burden of psoriasis.Results In 2017, the global age-standardized prevalence rate of psoriasis was 811 per 100,000 population, approximating to 0.84% of world population or about 64.6 million individuals. The incidence of new cases increased from 92 per 100,000 in 1990 to 99 in 2017. The highest rates were recorded in North America and Western Europe, while the lowest rates were found in Asia and Western Pacific regions. The age distribution shows a rising rate of incidence from the second decade, peaking at 55-60 years. Women are slightly more likely to be affected. ConclusionsThe global incidence of psoriasis has been rising over the last three decades. The burden of the economic and psychosocial suffering caused by psoriasis calls for resource allocation and a multidisciplinary approach to address this common medical condition. Key MessageThe prevalence, incidence, and the burden of suffering caused by psoriasis have been rising over the past 17 years, despite efforts at improving diagnosis and treatment.

L-serine is a non-essential amino acid that is de novo synthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, L-serine is a precursor of a number of important compounds. Serine biosynthesis defects result from deficiencies in PGDH, PSAT, or PSP and have a broad phenotypic spectrum ranging from Neu-Laxova syndrome, a lethal multiple congenital anomaly disease at the severe end to a childhood disease with intellectual disability at the mild end, with infantile growth deficiency, and severe neurological manifestations as an intermediate phenotype. In this report, we present three subjects with serine biosynthesis effects. The first was a stillbirth with Neu-Laxova syndrome and a homozygous mutation in PHGDH. The second was a neonate with growth deficiency, microcephaly, ichthyotic skin lesions, seizures, contractures, hypertonia, distinctive facial features, and a homozygous mutation in PSAT1. The third subject was an infant with growth deficiency, microcephaly, ichthyotic skin lesions, anemia, hypertonia, distinctive facial features, low serine and glycine in plasma and CSF, and a novel homozygous mutation in PHGDH gene. Herein, we also review previous reports of serine biosynthesis defects and mutations in the PHGDH, PSAT1, and PSPH genes, discuss the variability in the phenotypes associated with serine biosynthesis defects, and elaborate on the vital roles of serine and the potential consequences of its deficiency.

SummaryWith the growth of cosmetic dermatology worldwide, treatments that are effective against skin diseases and augment beauty without prolonged recovery periods, or exposing patients to the risks of surgery, are increasing in popularity. Chemical peels are a commonly used, fast, safe and effective clinic room treatment that may be used for cosmetic purposes, such as for fine lines and photoageing, but also as primary or adjunct therapies for acne, pigmentary disorders and scarring. Clinicians are faced with specific challenges when using peels on ethnic skin (skin of colour). The higher risk of postinflammatory dyschromias and abnormal scarring makes peels potentially disfiguring. Clinicians should therefore have a sound knowledge of the various peels available and their safety in ethnic skin. This article aims to review the background, classification, various preparations, indications, patient assessment and complications of using chemical peels in ethnic skin.What's already known about this topic?• Chemical peels are efficacious therapeutic interventions for many skin disorders.• Many peels exist; however, not all are safe for use in ethnic skin.• Darker skin types have an increased risk of adverse events from chemical peeling such as pigmentary disorders. What does this study add?• This is an up-to-date review of the various peeling agents and their indications for use in ethnic skin.• It provides a summary of newer peeling agents.• It gives practical tips on performing chemical peeling safely and effectively in ethnic skin.

Our results suggest that PCL-based dermal fillers offer longer-lasting performance over NASHA-based dermal fillers in NLFs treatment.

Skin lightening (SL) for cosmetic reasons is associated with profound negative impacts on well-being and adverse effects on the skin, resulting in immense challenges for dermatologists. Despite current regulations, lightening agents continue to dominate the cosmetic industry. In this review, our international team of dermatologists tackles the topic of SL as a global public health issue, one of great concern for both women’s health and racial implications. We have examined SL in Africa, Asia, the Middle East, and the Americas. We aim to inspire a global discourse on how modern dermatologists can utilize scientific evidence and cultural competency to serve and protect patients of diverse skin types and backgrounds. In doing so, we hope to promote healthy skin and inclusive concepts of beauty in our patients and society.

Background: Cosmetic surgery and esthetic procedures have become a billion dollar industry owing to the ever-growing demand of the population to stay young. The injectable treatments including fillers and botulinum toxin have become highly popular because of their quick, predictable and lasting results in the management of facial wrinkles and rejuvenation. Although these treatment modalities are relatively safe, they are associated with certain side effects. Aims:In this review, we will focus on the complications of fillers and botulinum toxin. Patients/Methods: The literature research considered published journal articles(clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) and reference lists of respective articles. Only articles available in English were considered for this review.Results: Brow ptosis and asymmetry are common adverse effects of botulinum toxin while the most common adverse effects associated with fillers are the local injection related effects manifesting as erythema, edema, pain, and ecchymosis. Conclusion:It is important that the treating physician is well verse with the various fillers and botulinum toxin complications and their management as some of the complications can be severely debilitating. K E Y W O R D Sbotulinum toxin, cosmetic surgery, filler, side effects | 571 KASSIR et Al.