Over 19,809 dermatologists and others interested in the field of dermatology attended the meeting March 8-12 in San Diego, California, USA. This event is the world’s largest dermatology meeting.

The plenary provided attendees the opportunity to hear from renowned experts on topics that impact dermatologists and their patients. It is the opportunity to present advances in health care concerns and changes in educational delivery tools as well. Below are topics of interest for both dermatologists and professionals in the cosmetics industry.

Photodermatology: past, present and future

Henry W. Lim, MD, FAAD

Dept of Dermatology, Henry Ford Health Detroit, Michigan, USA

Dr. Lim gave the Clarence S. Livingood, MD Memorial Award and Lectureship: “Photodermatology: Past, Present and Future”

Dr. Lim reviewed the history of photodermatology and the photobiology as related to skin. He started his presentation with the description of visible light as observed by Sir Isaac Newton in 1669. Dr. Lim detailed the progress made in phototherapy, photodermatoses, and photoprotection through the ages. He started with Isaac Newton’s discovery in 1665 that a prism bends visible light and that each color refracts at a slightly different angle depending on the wavelength of the color. In 1903 Niels Finsen received the Nobel Prize for his therapeutic results using ultraviolet radiation to treat lupus vulgaris. This marked the start of modern phototherapy. Although ultraviolet (UV) therapy is used for a varied of skin conditions, long-term exposure to UV radiation from sunlight can cause premature skin aging (photoaging) resulting in wrinkles, altered pigmentation, and loss of skin tone. Dr. Lim along with collaborators investigated the role of matrix-degrading metalloproteinases, a family of proteolytic enzymes, as mediators of collagen damage in photoaging. In other words, confirming that UV exposure promotes skin photoaging (1). Dr. Lim went on to study the difference between photoaging presentation in dark skin and light skin when exposed to visible light and UVA 1 on conditions aggravated by sun exposure. In recent years studies have shown the negative impact of visible light on skin health, particularly for people of color (​​​​​​​2). Regarding future application of phototherapy, Dr. Lim advised potential use of photobiomodulation, a non-invasive form of phototherapy red light wavelength a portion of visible light spectrum, and near infrared have potential to be used to treat radiation dermatitis, acne, skin rejuvenation, wounds, and scars. Infrared radiation (IR) is under evaluation for hair restoration. Further, new knowledge is being gained understanding the biologic effects of electromagnetic radiation beyond the UV spectrum, i.e., visible light /IR and interactions with exposome and the microbiome.

Lectureship Title: Sensing Inflammation At The Barrier

Brian Kim, MD, FAAD, Professor and Vice Chair of Research in the Department of Dermatology at the Icahn School of Medicine at Mount Sinai, New York, USA

Dr. Kim is a leading researcher in the study of patients with itch and other skin conditions focusing on mechanisms that control neuroimmune interactions at the skin barrier surface. His goal is to understand the regulatory mechanisms that control neuroimmune interactions at the skin barrier surface and how immune responses interface with the sensory nervous system to regulate inflammation, sensation, and immunity. Dr. Kim is a pioneering researcher studying cytokine biology, the communication between the immune system and the nervous system and how the immune system relays sensations back to the brain and regulates organ physiology and immune response. The discovery of itch-specific receptors and associated pathways that signal itch sensations is advancing the knowledge in how these pathways suppress itch. A recent paradigm shift is that in the past itch was not viewed as a disease, rather a symptom of a primary disorder. Currently the thought is that itch can be relieved in the absence of controlling the causing disease. An example are the opioid receptor-targeting agents are leading the way to advance development of new treatments and are providing increased insight in understanding itch biology. Opioid receptors are found in different cell types, they are well-known for their function on neurons. Endorphins bind to mu-opioid receptors (MORs) activation of this pathway is found to be very effective to alleviating pain. Activation of MOR can potentially stimulate or intensify the sensation of itch. On the other hand, another opioid receptor, the kappa-opioid (KOR) activates sensory neurons to suppress both pain and itch. These observations have helped to clarify the peripheral and central pathways that promote itch sensations and have generated heightened interest in further studies to understand the mechanism of itch suppression, via MOR and KOR receptor pathways (3, 4, 5, 6).

Zoe Draelos MD, Dermatology Consulting Services, Consulting Professor, Department of Dermatology, Duke University School of Medicine, North Carolina, USA

Dr. Draelos was session chair for The Science of Cosmeceutical and Nutraceuticals which was well-attended. The session reviewed the science surrounding topicals and oral ingredients claimed to enhance the appearance of skin. Topical skin care ingredients discussed included peptides, exosomes, growth factors, and DNA repair agents that were assessed for their value in skin care regimens. The aim of the session was to aid the attendee in assessing the current state of cosmeceutical and nutraceutical science.

Skin of Color Needs

Dr. Draelos gave the initial presentation addressing skin of color needs. The skin barrier of people of color when evaluated for transepidermal water loss is higher than Caucasian skin, indicating a more fragile barrier and a tendency for sensitive skin. However, when skin hydration is measured using corneometry, a method based on the principle that water within the skin conducts electricity, skin conductance is higher in African American and Hispanic persons, indicating that compared to Caucasian skin, they have a higher water content. Regarding lipid content, skin of color has a higher lipid content compared to Caucasian skin, ceramide content is about 50% lower compared to Caucasian and Hispanic skin. The ration ratio of cholesterol: fatty acid is also different in African American skin. The stratum corneum (SC) is more compact in African American, SC is 20 layers compared to 16 layers in Caucasian skin. African American SC has 2.5 times greater desquamation compared to Caucasian skin. The dermis of African American skin is thicker than Caucasian skin and is more resistant to effects of photodamage and aging. With respect to pigmentation, African American (AA) skin contains more eumelanin, the darker form of melanin and Caucasian skin contains higher levels of pheomelanin. The pH of African melanocytes is neutral and Caucasian melanosomes is acidic, tyrosinase, an enzyme responsible for melanin production is more active at neutral pH. There is also a higher melanosome transfer to keratinocytes in AA skin compared to Caucasian skin. Numerous pigment(s) brightening ingredients are available in the marketplace. They include hydroquinone, kojic acid, retinol, Vitamin C; these ingredients may be too irritating for skin of color, other ingredients with less irritation potential include niacinamide, azelaic acid, silymarin, arbutin and tranexamic acid. All skin types need sun protection. AA skin can benefit from tinted sunscreens that can protect against dyspigmentation associated with exposure to visible light. Black, yellow, and red iron oxide colorants combined with tinted titanium dioxide can be added to inorganic sunscreens to block UV and visible light while providing suitable color enhancing capability and minimizing the undesirable white cast on darker skin (7).

Late Breaking Cosmeceuticals 2024

Joshua Zeichner, MD, Associate Professor of Dermatology, Icahn School of Medicine at Mount Saini, New York, NY, USA

Dr. Zeichner discussed a novel multi-weight hyaluronic acid plus antioxidant complex. Hyaluronic acid (HA) is found in the extracellular matrix of skin. It functions as a humectant that can bind 1,000 times its mass with water. HA concentration and synthesis decreases in aging skin. Reactive oxygen species and other free radicals degrade HA. Dr. Zeichner presented data showing that an HA complex with the antioxidant glycine saponin induced endogenous HA synthesis in fibroblasts and decreased the degradation rate of HA by 54%. Another ingredient, acetyl dipeptide cetyl ester was shown to reduce irritation in skin and protect collagen-making fibroblast cells. Acetyl dipeptide-1 cetyl ester is a lab-engineered synthetic peptide that combines acetic acid and cetyl alcohol with dipeptide-1. The dipeptide is found naturally in the body and is composed of amino acids arginine and tyrosine. It helps to maintain the skin’s elasticity and can be considered an anti-glycation agent (8). Dr. Zeichner discussed lotus sprout extract (Nelumbo nucifera) as an effective skin brightening agent. It possesses antioxidant, anti-inflammatory, and soothing properties. Dr. Zeichner reported on the skin brightening effects of the lotus sprout extract showing exceptional potential to improve the appearance of skin (9).

Senescence Concepts and Cosmeceuticals 2024

Edward L. Lain, MD, FAAD, Chief Medical Officer, Sanova Dermatology, Austin, Texas, USA

Senolytics is relatively new approach that targets and removes senescent cells in skin to “treat” aging. Senescent cells are commonly referred to as zombie cells, accumulate over time causing inflammatory reactions and promoting skin aging. Dr. Lain explained that the immune system usually clears senescent cells, however when many are present at once or constantly produced by oxidative stress over time, they accumulate in skin. In this situation they induce inflammation and cause other cells to become senescent. The aging process increases dysfunction of the innate and adaptive immune response. This is referred to as immunosenescence, one can observe an increase in the number of memory T cells to respond to lingering levels of low-grade inflammation and can result in immune dysfunction, this condition is also referred to as inflammaging. Melanocytes, the pigment producing cells in skin are subject to senescence from prolonged exposure to Ultraviolet light and via DNA damage drive cells into senescence, and detrimental to skin. Dr. Lain reported on studies that provide a proof of concept that senescent melanocytes affect keratinocyte function and act as drivers of skin aging. Senolytic agents can rescue the surrounding cells to act as anti-aging agents by eliminating accumulation of senescent cells (10). Quercetin is an example of a natural ingredient that has this potential.