Hyperpigmentation is a skin condition that is often seen in aesthetic practice. It can be difficult to treat, and the first step of any treatment should be a thorough consultation in which the healthcare professional determines the type of pigmentation that the patient has; the most appropriate treatment can then be determined. This step is essential, as if hyperpigmentation is not treated effectively, its appearance can become worse than before treatment.
Hyperpigmentation is the overproduction of melanin by the melanocytes. The melanin is distributed horizontally and vertically, meaning that the pigment spreads to the side of the cells and to the skin in a pyramid fashion.
Melanocytes are melanin-forming cells which are largely in the skin, located in the bottom layer of the skin's epidermis. Melanin is predominately responsible for the skin's colour based on the amount and type of melanin pigment produced. Melanocytes are responsible for all skin pigmentation disorders and are extremely sensitive and unstable cells. Normal skin pigmentation is a complex process, which is normally influenced by genetics, hormones, injury, sun and heat.
Melanocytes
Melanocytes make two forms of melanin: eumelanin and pheomelanin. The relative amounts of these two pigments help to determine the colour of a person's hair and skin. People who produce mostly eumelanin tend to have brown or black hair and dark skin that tans easily. Eumelanin also protects skin from damage caused by ultraviolet (UV) radiation in sunlight. However, although people with this skin type are more protected from UV radiation, they are more likely to suffer from uneven skin tone and pigmentation issues.
People who produce mostly pheomelanin tend to have red or blonde hair, freckles, and light-coloured skin that tans poorly. Because pheomelanin does not protect skin from UV radiation, people with more pheomelanin have an increased risk of skin damage caused by sun exposure.
Pigmentation disorders
Melasma/chloasma
The aetiology of melasma remains poorly understood, but there are some known triggering factors, including sun exposure, pregnancy, sexual hormones, inflammatory processes of the skin, use of cosmetics, steroids and photosensitising drugs (Handel et al, 2014a). There is also a clear genetic predisposition; some studies have reported that 55–64% of patients with this condition have a positive family history (Moin et al, 2006; Adalatkhah et al, 2008; Handel et al, 2014b). It is more commonly seen in women, and is characterised by irregular brown, grey, blue or black macules and plaques, mainly on the face, neck and décolletage (Bandyopadhyay, 2009). There are three clinical types of melasma–centrofacial, malar and mandibular (Deo et al, 2013)
Post-inflammatory hyperpigmentation
Various types of inflammation (such as acne, eczema and allergic reactions) or trauma to the skin (such as surgery and previous aesthetic procedures, including microdermabrasion, lasers or chemical peels) can cause the release of inflammatory cells that cause melanocytes to produce more pigment in the skin (Australian College of Dermatologists, 2019). In cases of severe inflammation or trauma, the bottom layer of the epidermis is disrupted, causing the pigment to leak into and become trapped in the dermis, resulting in a deeper pigmentation that is more resistant to treatment. Post-inflammatory pigmentation is characteristed by flat, brown or black spots on the skin, which can appear anywhere on the body.
Genetic pigmentation disorders
In most individuals, melanocytes are only present in the epidermis and hair follicles. However, in some people, these cells are present in the dermis; this causes a condition known as dermal melanocytosis. Dermal melanocytosis encompasses a broad range of conditions, including Mongolian spots, Naevus of Ota, Hori's naevus and naebus of Ito. These conditions cannot be treated effectively with products, and laser treatment is required for good results.
Sun-induced pigmentation disorders
Pigmentation changes to the skin as a result of sun exposure is classically displayed as ephelides—commonly known as freckles. However, with age, this can also appear as solar lentigo—dark (hyperpigmented) lesions caused by natural or artificial ultraviolet (UV) light. These are often called ‘age spots’ or ‘sun spots’.
Those with darker Asian, Mediterranean or African skin tones are more prone to hyperpigmentation (Kim and Cho, 2010), especially if they have undergone excess exposure to sunlight. Indeed, the main risk factor for hyperpigmentation is exposure to UV radiation, but hormonal factors have also been implicated in the pathogenesis of more severe forms of hyperpigmentation, such as melasma (Bandyopadhyay, 2009)
Consultation
When a new patient presents to clinic, it is imperative that a full medical history is taken before starting the consultation. The consultation process should allow the practitioner to perform a comprehensive skin analysis, establish a diagnosis, enable treatment of the problem and monitor treatment progress and outcomes.
After the consultation has taken place, the healthcare professional should talk the patient through all of the suitable treatment options available to them specifically. Obagi's (2014) skin classification can be used to assist in selecting the best treatment for the patient. According to Obagi (2014), skin is classified by thickness (thick, medium, thin), colour (original, deviated); oiliness (oily, dry); laxity (skin, skin + underlying muscle); and fragility (strong, fragile).
Essentials in hyperpigmentation treatment
Restoring barrier function
To start treating hyperpigmentation, first we need to restore the barrier function. In doing so, the following criteria should be addressed:
Managing expectations
As with any treatment, it is important that the patient's expectations of treatment are managed, and this should be done during the consultation period, prior to any treatment taking place. Patients with hyperpigmentation usually require ongoing treatment, and it can take several months for patients to see satisfactory results. It takes at least 2–6 weeks for treatments to take effect and 5 months of daily use for maximum results (Sibley, 2014).
In order to manage the patient's expectations, the healthcare professional must provide a comprehensive picture of what treatment involves. This includes fully explaining any unpleasant side-effects of treatment, such as skin peeling, redness, irritation, itching and burning. It can be useful to provide some tips on managing these side-effects, such as decreasing frequency of application if irritation becomes a recurring problem.
Treatment options
There are a number of ways to treat pigmentation. Topical approaches to pigmentation treatment include skin peels, laser treatments, mesotherapy and SPF. Each approach has its own benefits and varying levels of downtime, but each works in an individual way to prevent and repair pigmentation.
Depigmenting agents
Several topical agents can be used to treat hyperpigmentation.
Hydroquinone
One of the most commonly used treatments for melasma is topical hydroquinone at concentrations of 2–4%. Hydroquinone exerts a depigmenting effect on the skin by inhibiting tyrosinase, and is known to cause reversible inhibition of cellular metabolism by affecting both DNA and RNA synthesis (Nordlund, 1988; Sibley, 2014). Although HQ is effective on its own, it can also be combined with other ingredients such as tretinoin, glycolic acid, kojic acid and azelaic acid (Guevara and Pandya, 2001). In the authors' experience, clinical improvements can usually be seen after 4–6 weeks; however, long-term effects can be difficult to achieve.
The Food and Drug Administration has expressed concern about side-effects associated with the topical use of hydroquinone, which can lead to a condition called exogenous ochronosis (Picardo and Carrera, 2007). Ochronosis presents as blue-black macules (or, a permanent form of hyperpigmentation) in the area of application, which usually occurs after prolonged use of hydroquinone in concentrations of 4% (Lawrence et al, 1988; Sibley, 2014). For this reason, patient education is essential when prescribing this course of treatment. Patient should be made aware of the intended duration of therapy. There is no substantial evidence to prove carcinogenicity (Desai, 2014).
Tyrosinase inhibitors
Tyrosinase is an enzyme that controls the synthesis of melanin (Iozumi, 1993). Because of this, its activity is thought to be a major regulatory factor in melanogenesis (Baumann and Allemann, 2009). Several products are available that contain ingredients that inhibit tyrosinase, thus decreasing melanin formation. These ingredients include aloesin, gallic acid, kojic acid (Lee et al, 2014), liquorice extract and paper mulberry (Sarkar et al, 2013).
Topical agents
Chemical peels
Superficial chemical peels are generally effective for the management of hyperpigmentation and melasma, when properly applied (Burns et al, 1997; Desai, 2014). Common options include glycolic acid 20–70%, salicylic acid 20–30%, trichloroacetic acid (TCA) 10-25%, or Jessner's solution. Pretreatment with a course of hydroquinone 4% topically can improve outcomes (Desai, 2014).
When chemical peels are applied to the skin, the top layer is shed, and this process can be used to treat mild discoloration. Moderate or deeper peels reach further into the skin and help to remove deeper pigmentation, but deeper peels are associated with longer healing times and an increased risk of side-effects. Treatment aims to unload the pigment from the skin. The authors recommend the use of products from ZO Skin Health, which work by controlling melanocyte activity.
Retinoids
Retinoids are a family of compounds derived from vitamin A, which includes betacarotene, retinol, tretinoin, tazarotene and adapalene (Baumann and Saghari, 2009). Retinoids are regularly used to treat melasma and post-inflammatory hyperpigmentation, and are generally well tolerated in pigmented skin (Geria et al, 2011).
Retinoids reduce hyperpigmentation by promoting the loss of melanin through the stimulation of keratinocyte turnover and reducing melanosome transfer (Vashi and Kundu, 2013).
Laser treatment
Laser and light-based therapies can be effective for patients with hyperpigmentation. In one study of female patients with melasma, low-fluence Q-switched Nd:YAG laser treatment was provided (Kauvar, 2012). Treatments were repeated at 4-week intervals. Most subjects showed more than 50% clearance of melasma 1 month post initial treatment. Side effects were mild. Four subjects noted temporary exacerbation of melasma after inadvertent sun exposure, but this resolved within several weeks of resuming the topical skincare regimen. Remission lasted at least 6 months (Kauvar, 2012).
Freckling and age spots can be lightened or removed using an alexandrite 755 nm laser which uses photoacoustic energy to target excess pigment and safely break down the excess melanin into tiny particles, which then shed away naturally (Patil and Dhami, 2008). However, the wavelength of this laser is only suitable for Fitzpatrick skin types I and II.
After-care and SPF
As with any aesthetic treatment, it is crucial that patients adhere to an effective after-care plan to maintain skin health and prevent any further damage from occurring. In the case of pigmentation disorders, anti-inflammatory, stimulating and pigment-correcting products are recommended. With all treatments, it is imperative that the patient is made aware of the importance of using SPF on a daily basis.
Conclusion
Pigmentation disorders can have a detrimental impact on a patient's confidence and quality of life. It is important that the healthcare professional has an in-depth understanding of the types of pigmentation disorders, their aetiology and all suitable treatment options, so that they can educate the patient and develop an effective treatment plan.