Laser therapy on colored skin.

What is colored skin?

Colored skin generally refers to non-white skin types, with a particular emphasis on Fitzpatrick V and VI skin phototypes. It is characterized by an increase epidermal melanin (a brown pigment), more widely distributed melanosomes (the one containing melanin granules inside melanocytes), Changing melanocyte responsive and hyperactive fibroblasts.

How does skin differ from colorpigmented White skin?

How melanin absorbs and disperses the energy transmitted from Ultraviolet radiation (UVR), people with colored skin experience less epidermal damage after UVR exposure and show fewer signs of photoaging than people with lighter skin types [1,2].

Colored skin almost always develops pigmentary changes when exposed to injury or inflammation (post-inflammatory hyperpigmentation and post-inflammatory hypopigmentation), while pigmentary changes are rare in white skin [3].

Melanin can act as competitive chromophore (a colour molecule absorbing transmitted energy), increasing the risk of side effects after epidermal injury from a To be [4].

People with colored skin have a higher predominance of hypertrophic scars and keloids after injury than those with white skin due to genetic factors associated with overactive fibroblasts [2,3].

What are the indications for laser therapy on colored skin?

The medical indications for laser therapy are similar regardless of skin color. However, women of color often seek treatment for hyperpigmentation and uneven skin color, as these are common cosmetic concerns [2].

Laser therapy can also be used to remove dark, thick, terminal hairs, which can lead to pseudofolliculitis barbae, folliculitis keloidalis nuchae, and folliculitis decalvans, conditions that are more common on colored skin. [5].

To be hair removal on colored skin

The safest laser for hair removal on people with colored skin is the long-pulse neodymium-doped yttrium-aluminum garnet laser (Nd: YAG).

• Its wavelength (1064 nm) is at the end of the melanin absorption spectrum.
• Nd: YAG laser results in sufficient thermal injury to thick dark hairs and saves epidermis [6].
• It allows energy to be delivered slowly, resulting in heat dissipation and cooling, and minimizes damage to the epidermis.

The use of the alexandrite laser (with its wavelength of 755 nm) has not been extensively studied in colored skin. It has been reported to cause blisters in patients with Fitzpatrick V and VI skin types. [7].

The use of a diode laser (with its 800nm wavelength) has been reported to be primarily safe with low complication rates, including the appearance of transient blisters and pigment disturbance. [8].

Rejuvenation of acne scars

Acne scars can be treated with either an ablative carbon dioxide laser or an erbium-doped yttrium-aluminum garnet (Er: YAG) laser, but it is best avoided on skin types V and VI, as thermal injuries they usually cause post-inflammatory hyperpigmentation. [9].

Non-ablative Nd: YAG laser has fewer side effects compared to ablative laser rejuvenation and produces comparable results.

Tattoo removal

Few studies have been reported on tattoo removal on colored skin. Blue / black charcoal based religious tattoos on Ethiopian patients with skin type V and VI have been removed by a Q-Switched Nd: YAG [10]. In this study, almost half of the patients developed mild post-inflammatory hyperpigmentation that lasted between 2 and 4 months.

Removing tattoos on colored skin can be difficult and unpredictable due to epidermal melanin, which absorbs transmitted energy and prevents ink from reaching the dermis.

What can help improve the results of laser therapy on colored skin?

Cooling

Cooling is used to protect the epidermis from thermal burns. [eleven].

• Cooling by contact, which depends on conduction, can be active (for example, through the use of sapphire laser windows or copper tips) or passive (for example, through the use of ice cubes).
• Non-contact cooling uses cold air convection or cryogenic cooling.

Technique

Epidermal injury should be carefully controlled on colored skin.

• An Nd: YAG laser with a long wavelength and longer pulse times is often the most suitable device for use on colored skin.
• A test pulse or pulses can be used to verify the immediate effects of the laser on the skin.
• Multiple short sessions can also help reduce epidermal damage compared to longer single sessions. [12].

Education

Patient expectations must be realistic and they must be informed about the risk of complications and side effects associated with laser therapies. [two].