Introduction
Hyperpigmentation is a common skin condition caused by increased or disordered deposition of melanin which results in those bothersome darkened patches on the skin (almost alway the face). It can affect both men and women and is affected by aging, medical conditions, or external factors. This article will focus mostly on the causes of hyperpigmentation, particularly with regards to aging, and the treatment optionns available . We will discuss the pathophysiological background (sciency bit – how the body makes the pigment and where it goes wrong in doing so), factors that worsen the outcome of hyperpigmentation (things you might be able to change), and I will be referring to research and guidelines from the British Association of Dermatology.
Pathophysiological Causes of Hyperpigmentation
Melanin (pigment that causes a tan) is synthesised by melanocytes, these are specialised pigment cells located in the bottom (basal layer of the epidermis. The process of melanin synthesis (called melanogenesis) occurs within tiny structures within cells (called organelles) known as melanosomes (Maresca, Flori & Briganti, 2009). Tyrosinase, an enzyme which plays a vital role in the synthesis and distribution of melanin (Winder et al., 2015) also helps control the rate at which melanin is produced. Melanin is then transferred to the protective, upper layers of the skin (the keratinocytes), providing colour (tan) to different areas of the skin (Costin & Hearing, 2007).
Ageing affects the production of melanin in older adults, leading to the appearance of pigmented skin changes, such as age spots or, to give them their correct, clinical name; solar lentigines (Kwon et al., 2016). Several age-related processes contribute to the development of these skin changes (remember we talked before about how the DNA replication gets a bit faulty as we age?), including increased melanocyte activity, diminished antioxidative defence systems, and the overproduction of growth factors, cytokines, and inflammatory mediators (Briganti, Picardo & Antille, 2003; Mates, Kumar & Szabo, 2009).
Moreover, chronological ageing and cumulative exposure to ultraviolet (UV) radiation both lead to structural and molecular alterations in the basal membrane – more commonly known as sun damage (Brennan et al., 2003), which subsequently impacts melanocyte activity, melanin distribution, and the overall appearance of the skin. Furthermore, age-related hyperpigmented spots tend to be abundant in sun-exposed areas, such as the face, hands, and arms; this further strengthens the argument for the role of sun exposure in exacerbating hyperpigmentation and the need for SPF to be used regularly (Grifoni et al., 2014).
Factors That Worsen the Outcome of Hyperpigmentation
1. Sun exposure: The biggest risk factor for the development of hyperpigmentation; sun exposure induces the production of melanin as a protective response. Extrinsic ageing, resulting from prolonged sun exposure, can lead to structural skin damage and promote conditions such as solar lentigines (Grifoni et al., 2014).
2. Hormonal changes: Hormonal imbalances can provoke the onset of hyperpigmentation, particularly during pregnancy or menopause. Melasma, otherwise known as chloasma, is an example of hormone-induced hyperpigmentation and is linked to the increased production of melanocyte-stimulating hormone (Kwon et al., 2016).
3. Inflammation: Post-inflammatory hyperpigmentation (PIH) emerging after skin injury, infections, or inflammatory conditions, may be more severe and persistent in ageing individuals. PIH can result from various conditions such as acne, eczema, or dermatitis (Callender et al., 2011).
4. Medications: Certain medications, including those for hypertension, hormonal therapy, or chemotherapeutic agents, can lead to drug-induced hyperpigmentation as they deposit in the skin or alter melanin production through various mechanisms (Dereure, 2001).
Treatment Options for Hyperpigmentation
1. Topical treatments: Topical bleaching agents, such as hydroquinone, glycolic acid, and kojic acid, aim to direct inhibition of tyrosinase, reducing melanin production. These agents are commonly used for melasma and PIH treatments (Lim, 1999; Taylor et al., 2009). However, the British Association of Dermatology recommends patch testing prior to treatment due to a potential local irritation risk (BAD, 2018).
2. Retinoids: Vitamin A derivatives, such as retinol or tretinoin, are effective in treating hyperpigmentation due to their exfoliative properties and ability to disperse epithelial melanin (Berardesca et al., 1991).
3. Laser and light therapies: Intense Pulsed Light (IPL) therapy and Q-switched lasers are both effective in treating hyperpigmentation by selectively targeting melanin deposits and melanosomes in the skin (Geddes et al., 2009). The British Association of Dermatology supports these as treatment options, with caution relating to adverse effects and scarring (BAD, 2018).
4. Chemical peels: These treatments use acid solutions containing alpha hydroxy
acids or beta hydroxy acids to cause controlled exfoliation of the skin, facilitating melanin dispersion and removal (Khunger, 2008). The choice of acid strength and type depends on the patient’s skin type and the severity of hyperpigmentation. However, chemical peels should be performed by trained professionals, and the British Association of Dermatology highlights the risk of scarring and PIH if not performed correctly (BAD, 2018).
5. Sun protection: I mean, this is the simplest measure, right? Wearing sunscreen with at least SPF 30 and broad-spectrum coverage, protective clothing, and avoiding excessive sun exposure, are crucial in preventing and managing age-related hyperpigmentation (Glaser et al., 2016).
6. Antioxidants: Applying topical antioxidants, such as vitamin C, vitamin E, and resveratrol, can help reduce oxidative stress that contributes to the development of hyperpigmentation. Oral antioxidants supplements may also offer some benefits (Bonina et al., 1996; Placzek et al., 2005).
7. Microneedling: Microneedling is a minimally invasive procedure that uses small needles to cause micro-injuries, stimulating skin regeneration and collagen production, which can help improve the appearance of hyperpigmentation (Ibrahim et al., 2015).
Conclusion
Hyperpigmentation in ageing is the result of many factors including complex pathophysiological processes involving increased melanocyte activity, diminished antioxidative defence mechanisms, and altered distribution of melanin. Several factors, such as sun exposure, hormonal changes, inflammation, and medications can exacerbate the severity of hyperpigmentation. Various treatment options are available, including the use of topical agents like retinoids, laser therapies, chemical peels, sun protection, and antioxidants. The selection of the most appropriate treatment should be based on the individual patient’s skin type and severity of hyperpigmentation. The British Association of Dermatology is clear about the importance of patch testing and professional application of certain treatments due to the risk of adverse effects. As ageing and sun exposure are shown to be significant contributing factors to hyperpigmentation, it makes sense to implement robust sun protection and as an aside, antioxidant supplementation may help with preventing and managing the condition.
References
BAD (British Association of Dermatology). (2018). Treatment of hyperpigmentation. Retrieved from https://www.bad.org.uk/for-the-public/skin-cancer/hyperpigmentation
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Callender, V. D., St Surin-Lord, S., Davis, E. C., & Maclin, M. (2011). Postinflammatory hyperpigmentation: etiologic and therapeutic considerations. American Journal of Clinical Dermatology, 12(2), 87-99.
Costin, G., & Hearing, V. J. (2007). Human skin pigmentation: melanocytes modulate skin colour in response to stress. FASEB Journal, 21(4), 976-994.
Dereure, O. (2001). Drug-induced skin pigmentation. Epidemiology, diagnosis and treatment. American Journal of Clinical Dermatology, 2(4), 253-262.
Geddes, E. R., Stout, A. B., & Friedman, P. M. (2009). Treatment of actinic purpura with a 595 nm pulsed dye laser with dynamic cooling device. Lasers in Medical Science, 24(6), 961-963.
