Pigmentation problems result from an increase in melanin in the epidermis, dermis or both. This can be due to an increase in melanin production by the melanocytes or an increase in the number of melanocytes. Epidermal pigmentation manifests as brown discolouration whereas dermal pigmentation manifests as bluish-grey discolouration. Asians are more prone to pigmentation problems due to the higher numbers of melanocytes in their skin.
Common pigmentation problems:
Freckles
Freckles are small brownish spots that appear on sun-exposed areas such as the face. They are usually <1cm in size. They are due to overproduction of melanin in the epidermis in response to UV exposure. They can come and go spontaneously depending on the degree of sun exposure.
Solar Lentigenes
Solar lentigines are related to long term sun exposure and resultant photodamage of the skin. They appear as brownish spots and can be >1cm in diameter. There is underlying over-proliferation of melanocytes as well as overproduction of melanin.
Melasma
Melasma is a common pigmentary condition affecting women more often than men. It is a long term and challenging problem to treat as the pathophysiology of melasma is complex and related to the interplay of genetic, hormonal and environmental factors such as sun exposure and smoking.
It can appear as brownish to greyish patches on the cheeks, forehead, temples, upper lip, nasal bridge and jawline.
Seborrheic Keratosis
Seborrheic keratosis is a non-cancerous skin growth that results from photoaging of the skin. It can vary in size from small to larger than 3 cm and tend to grow in size very slowly with time. They have a stuck-on appearance and may occur on any part of the body including the face.
Post-inflammatory Hyperpigmentation
Post inflammatory hyperpigmentation results from an increase in melanin levels in the epidermis or dermis or both in response to inflammatory processes such as acne, contact dermatitis, atopic dermatitis or trauma.
On a cellular level, there are 2 important processes that lead to this condition:
- Overproduction of melanin by the melanocytes due to stimulation by chemical mediators released in the inflammatory process and increased transfer of melanin granules to adjacent keratinocytes.
- Destruction of the basal cell layer between the epidermis and dermis, migration of melanin into the dermis and increase in melanophage numbers in the upper dermis.
Hori’s Nevus
Hori’s nevus is also known as acquired nevus of ota-like macules (ABNOM). It most commonly develops in Asian women between 30-50 years old. They appear as bluish grey spots and can occur on the malar prominences of the cheeks, nose and forehead. It is caused by abnormal melanocyte collections in the dermis (dermal melanocytosis). The exact cause is unknown but the condition is likely related to genetics and hormones rather than to UV exposure.
Treatment of pigmentation
Skincare:
- Broad spectrum sunblock with blue light protection
- Cosmoceuticals with lightening ingredients such as licorice, arbutin, niacinamide, azelaic acid, kojic acid, retinol, tranexamic acid etc.
Topical creams:
- Prescription bleaching creams such as hydroquinoine and tretinoin
Oral medication:
- Oral medications such as tranexamic acid is useful in treatment of melasma
Aesthetic treatments:
- Chemical peels eg. Glycolic acid gently exfoliate the skin and increase epidermal cell turnover which helps to reduce melanin content in the epidermis and subsequent lightening of pigmentation problems
- Intense pulsed light (IPL) uses broad spectrum light to target pigment lesions via a photothermal effect. It is effective for epidermal pigmentation problems such as freckles and lentigines. However, care must be taken in the administration of this treatment in darker skin individuals as there is a risk of post inflammatory pigmentation due to the thermal effect involved.
- Non ablative laser treatments such as nanosecond and picosecond nd-YAG lasers can target melanin and break down melanin via a combination of photothermal and photoacoustic effects. It is the gold standard treatment for pigmentation problems in Asian skin types. It is also the only effective treatment for Hori’s nevus as topical treatments are unable to remove the pigmentation which is present deep in the dermis.
- Ablative lasers such as erbium YAG and carbon dioxide lasers have a role in treating seborrheic keratoses by directly ablating the lesion from the skin surface.