Dr Taka Chinyoka
It is widely accepted among scientists that all humans share a common ancestor and due to evolutionary pressure, following migration to the north and southern hemispheres with different climate conditions and UV light exposure, our skin colour changed to adapt to the relevant level of UV light with altered melanin levels in the skin, this simply to maximise survival chances and perpetuation of our species.
This possibly led to hereditary changes and consequent racial or ethnic differences in skin properties or rather racial disparities. The resultant differences in melanin production, distribution and degradation among other factors determine the racial differences. There is up to five times more UV light penetration in Caucasian skin than black skin across the upper layers of the skin. In Namibia, we exist in all skin types with the majority being brown to black (Fitzpatrick 4 to 6) with a significant population being fairly skinned and darker Caucasians (Fitzpatrick 2 to 3).
There are a lot of myths, misuse and misinformation concerning lightening agents among the population. A belief that lighter or fairer skin is more beautiful reins deep in the minds of many, especially the darker skinned. It is because of this that there is rampant abuse and misuse of these lightening molecules in the hope of becoming fairer. While I explained in brief the generally accepted scientific explanation, or rather evolutionary reasons for darker skin, the issue of skin colour and beauty remains, controversial, sensitive and wholly subjective among different ethnicities.
In the Cosmetic medicine service, however, the view is that everyone is beautiful in their own skin. Of course there are other parameters that are objectively used to judge beauty. This is a story for another day.
A number of lightening agents are widely used in the treatment of different types of localised or generalised dermatologic pigmentary disorders and in cosmeceuticals with excellent results. These agents are relatively safe if used in correct doses for appropriate indications and this is extremely important to remember.
Lightening agents, also referred to as bleaching or whitening agents fall into different categories with some that inhibit melanin production through different mechanisms e.g. Hydroquinone, antioxidants e.g. glutathione, vitamin C, accelerators of epidermal turnover and desquamators e.g. retinoid, AHAs and UV absorbers like sunscreens among others. They also come in different preparations including topical applications like creams, oral preparations and injectables.
The common skin whitening agents are: Hydroquinone, azelaic acid, kojic acid, arbutin, retinoids, mequinol, niacinamide, soy, vitamin c, corticosteroids, licorice, hydroxystilbene, alosein, glutathione, glycolic acid, n acetyl glucosamine, gentisic acid, green tea and melatonin.
In aesthetic medicine practice, the application of different types of these preparations yield awesome results in restoring even tone and treating dyschromia, preventing post inflammatory hyperpigmentation prior to peeling darker skin and in skin conditioning and rejuvenation. In my practice I prefer using azelaic acid, kojic acid, retinoids, vitamin c, licorice, glutathione, glycolic acid and n-acetyl glucosamine to achieve excellent results.
Hydroquinone is the most commonly used and abused, there has been concern on its use with other researchers insisting on thorough safety reviews citing long term effects. However other scholars conclude that data so far suggest that it is reasonable to use Hydroquinone for treating hyperpigmentary disorders at concentrations below 5%HQ.
Despite the remarkable overall safety of hydroquinone, it has potential adverse effects.
Adverse events reported with HQ use include erythema, permanent leukoderma, skin irritation, contact dermatitis, cataract, pigmented colloid millium, nail pigmentation or discoloration, loss of skin elasticity, impaired wound healing, hypopigmentation of the surrounding normal skin that has been treated with HQ (“halo effect”) and post-inflammatory hyperpigmentation.
An uncommon but serious adverse effect of HQ is exogenous ochronosis. This disorder is characterised by progressive darkening in the treatment area exposed to hydroquinone. It can be extremely difficult to reverse to any degree. Exogenous ochronosis is typically associated with frequent use of very high concentrations of HQ on a long-term basis although it can still occur with short-term use of 1 to 2% HQ.
In Europe, over the counter use of Hydroquinone is banned with the USFDA expressing the same likelihood. An illicit market thrives in Namibia for these products and thus danger continuously looms among the population.
*is a GP and Aesthetic Physician based at the New Soweto Medical Centre in Katutura.E-mail: wellcare@iway.na