Acne vulgaris, commonly known as acne, is a prevalent skin disorder characterized by lesions including pimples, whiteheads, blackheads, and inflamed red skin areas like cysts. These blemishes arise due to the clogging of pores from excessive oil, dead skin cells, and bacteria, primarily affecting hair follicles and oil (sebaceous) glands.
Acne predominantly appears on the face, forehead, chest, shoulders, and upper back. While it can develop in individuals of any age, it is frequent among adolescents and young adults, with about 80% of individuals aged 12 to 30 encountering it. Various genetic and environmental factors, such as hormonal changes, stress, and humidity, contribute to its onset.
Acne is a multifactorial skin condition influenced by genetic and environmental factors. Acne has a substantial heritability component. Past twin studies have estimated the acne heritability at 80%, suggesting that shared genetic variants play a significant role in acne. Scientists have identified several genes that show a potential association with acne development. Here are some of the main genetic components linked to acne:
The Transforming growth factor-beta 2 (TGFB-2) gene is pivotal in skin cell differentiation and function. Research has illuminated its involvement in the mechanisms underlying acne development. Over-proliferation of skin cells can obstruct normal hair growth, resulting in comedones, Cutibacterium acnes (bacteria) infection, and accumulation of dead skin cells.
Furthermore, TGFB-2 modulates sebum production by the sebaceous glands. A malfunctioning TGFB2 gene may culminate in excessive sebum production, a trait observed in acne patients. This gene also orchestrates the body’s immune response to acne. A compromised TGFB-2 function can lead to a diminished or impaired immune response, thereby exacerbating acne proliferation. Notably, research has demonstrated that individuals with acne typically exhibit reduced expression of the active TGFB2 gene compared to individuals with clear skin.
A 2014 GWAS showed that imbalances in TGFβ-driven signaling play a significant role in acne vulnerability. Another study published in August this year implicated the influence of TGFB2 variant rs1256580 in acne.
IL-1α is a cytokine, a type of immune system messenger, consistently produced in minimal amounts by keratinocytes (a type of skin cell) and immune cells when activated. Research indicates that IL-1α plays a role in the initial phases of acne development. In particular, IL-1α might elevate the generation of keratinocytes and enhance the propensity of dead keratinocytes to adhere together, leading to blocked skin pores. These clogged pores can become a breeding ground for bacteria, including Cutibacterium acnes. This bacterium potentially contributes to the onset of acne by prompting the release of inflammatory proteins from immune cells.
Moreover, researchers believe IL-1α induces the secretion of other inflammatory cytokines from various skin cells. As a result, variations in the IL1A gene might contribute to acne development by elevating IL-1α production and encouraging inflammation. For example, this 2010 study found a positive association between the minor “T” allele of the IL1A +4845(G>T) SNP and acne. Another 2014 case-controlled study conducted in the Pakistani population revealed a significant association between the variant genotypes of IL-6-572 and IL-1A-889 and the development of acne. The study’s conclusions propose that the IL-6-572 “C” and IL-1A-889 “T” alleles might play a role in acne pathogenesis within the Pakistani demographic.
The TNF gene, Tumor Necrosis Factor, plays a critical role in the body’s immune response. It provides instructions for producing a protein called tumor necrosis factor-alpha (TNFα), which is involved in systemic inflammation and is a member of a group of cytokines that stimulate the acute phase reaction.
Inflammation is a fundamental factor in acne progression. Individuals with acne exhibit elevated expression of the TNF gene in their skin, which activates other cytokines, intensifying the inflammatory response. A 2014 meta-analysis showed that -308 G/A polymorphism in the TNF gene contributes to acne vulgaris risk, especially in Caucasian populations.
A two-stage GWAS in 2014 that investigated the Han Chinese population, involving 2,916 severe acne cases and 4,716 controls, pinpointed two novel potential SNPs: rs747650 and rs1060573. A subsequent 2021 meta-analysis confirmed that the “G” allele of rs747650 of the DDB2 gene increased the risk for severe acne.
A systematic review and meta-analysis published in 2021 showed that the FST rs629725 “A” allele poses a modest but significantly increased risk for acne.
Other single nucleotide polymorphisms (SNPs) that showed significant associations included:
Acne presentation
Severe acne (2018 genome-wide meta-analysis)
Acne is one of the most widespread dermatological conditions globally. Its epidemiology is extensive, spanning various ages, genders, and regions. Here’s an overview of the epidemiology of acne:
Acne is most prevalent during adolescence, affecting nearly 85% of teenagers to some extent.
While it’s primarily associated with puberty, about 50% of individuals in their 20s and 30s also experience acne. It can persist into one’s 40s and beyond for some people.
Both males and females are affected, but the age of onset, severity, and persistence might differ.
Acne prevalence can vary by region and ethnicity. However, it’s widespread across all racial and ethnic groups. Some studies have shown that certain ethnic groups might experience more acne-related post-inflammatory hyperpigmentation.
Diet, stress, urban living, and exposure to environmental pollutants have all been proposed as factors that might increase acne prevalence or severity, but direct correlations are still under study.
Contrary to popular belief, hygiene is not a direct cause of acne, though proper skin care can help manage and reduce its severity.
Individuals with acne may experience other skin conditions or health issues. Additionally, the psychosocial impact of acne is notable, with some individuals developing depression, anxiety, or reduced self-esteem.
Acne ranks as the 8th most common disease globally. The global prevalence significantly impacts the quality of life and is a notable economic burden due to treatment costs and lost productivity.
The overall prevalence of acne seems stable over time. However, the awareness, diagnosis, and treatment options have evolved in the recent times.
Acne is a complex condition that arises due to the interplay of various biological factors:
The skin contains sebaceous glands that produce an oily substance called sebum. Sebum’s primary function is to lubricate the skin and hair. However, excessive sebum production can clog hair follicles.
Human skin continuously renews itself. As new cells are produced, old cells die and are shed. In people with acne, this process of shedding dead skin cells is altered, leading to a buildup of dead skin cells in the hair follicle.
The combination of excess sebum and buildup of dead skin cells can block the hair follicles, forming a comedo – the earliest acne lesion. Closed comedones are called whiteheads; they become blackheads if they open up to the skin surface.
The sebaceous gland is conducive to the bacteria Propionibacterium acnes (P. acnes) to thrive. In certain conditions, these bacteria multiply rapidly in the blocked follicle. They digest the sebum and produce waste products and fatty acids, causing irritation and inflammation in the surrounding tissue.
The body’s immune response to the rapid multiplication of P. acnes and the waste products they produce leads to inflammation. This results in the redness, swelling, and pus characteristic of acne pimples or pustules.
Hormonal changes, particularly the increase in androgens during puberty, can enlarge the sebaceous glands, prompting them to produce more sebum. Hormonal changes during menstrual cycles and due to conditions like polycystic ovary syndrome (PCOS) can also cause acne outbreaks.
As discussed earlier, genetics plays a significant role in acne. If your parents had acne, you’re more likely to develop it.
Understanding the biology of acne is crucial for its effective treatment, which can range from topical treatments to address bacterial growth and reduce oil to oral medications that manage hormonal fluctuations or reduce inflammation.
Treatment depends on the severity and type of acne. Here are some general treatment options for acne:
Gentle cleansing, moisturizing, and sun protection are key. Non-comedogenic and oil-free products can reduce pore-clogging.
Though the connection between diet and acne isn’t definitive, some people find that certain foods exacerbate their acne. Reducing dairy or high glycemic index foods might be beneficial for some.
It’s essential to consult a dermatologist to determine the most appropriate treatment for individual cases. Some treatments, like isotretinoin, have significant side effects and require monitoring. Moreover, what works for one person might not work for another, and treatment can sometimes take weeks or even months to show significant results.
The LifeDNA skincare report takes a deep dive into your genetic makeup that helps you to understand your skin-related characteristics such as hydration level, collagen quality, and sensitivity to environmental factors like UV rays. Utilizing your DNA data, the report offers personalized skincare ingredient suggestions and lifestyle advice to help you maintain glowing skin.
The LifeDNA Skincare report covers an analysis of the Potential for Severe Acne. Get yours here.
*Understanding your genetics can offer valuable insights into your well-being, but it is not deterministic. Your traits can be influenced by the complex interplay involving nature, lifestyle, family history, and others.
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