Written by Dr. Katie Wang
Edited by Dr. Paul M. Graham
Post-inflammatory hyperpigmentation (PIH), also known as dark spots, is one of the dermatologists most difficult problems to treat. This is a very common problem that is often disregarded or not treated appropriately within doctor’s offices, hence a need for more tailored treatment by a dermatologist. Regardless of the cause, PIH can have a tremendous effect on the quality of life of patients. Therefore, proper treatment is vital and should be implemented early to prevent long-term consequences.
We briefly introduced this topic and explained the mechanism behind the cause in our first article entitled “The War on Skin Pigmentation: Part 1“. As previously described in more detail, the first line treatments for PIH are topical medications such as hydroquinone, retinoids, and azeleic acid. In Part II of this series on skin pigmentation, we will explore several alternative options that can be used to combat this difficult problem.
Laser therapy has been a promising innovation that has been shown by small studies to improve the appearance of PIH. This works similarly to the treatment of melasma, another common and frustrating pigmentary disorder often seen in women. Several studies have found improvement in pigmentation using a 1064-nm Q-switched Nd:YAG laser, a 1550-nm non-ablative erbium laser, a Q-switched ruby laser, and a fractional carbon dioxide (CO2) laser. The fundamental principle behind the use of lasers to treat pigmentary disorders is the idea that when a specific wavelength of light (energy) is delivered to the pigment molecule (chromophore) during a period of time, the pigment is damaged, causing elimination from the body.
One important factor that is vital to preventing surrounding tissue damage is the period of time that the energy is delivered. The laser pulse needs to be shorter than the time it takes for half of the pigment molecule to cool, allowing the energy to be limited to the area of pigment without causing surrounding tissue damage. This concept is called thermal relaxation time and although it may seem confusing, it is essential for the proper treatment of pigmented lesions. Additionally, the long wavelength of the Nd:YAG laser allows for deeper skin penetration and is safer in darker skin types; whereas shorter wavelength lasers may cause damage of normal skin pigment in darker-skinned patients.
For more information on lasers, please check out our article entitled “Cosmetic Laser Procedures: The Basics“.
As mentioned previously, various reports describe the improvement in PIH after treatment with a 1064-nm Q-switched Nd:YAG laser, a 532-nm Q-switched Nd:YAG laser, a Q-switched ruby laser, a 1550-nm erbium fractional laser, and fractional carbon dioxide (CO2) lasers.
It is important to recognize that PIH may be a potential side effect of laser therapy in certain skin types. Although rare, this risk is highest among individuals with darker skin color. Unfortunately, this population is the most likely to need treatment for PIH. This reinforces that laser treatment should only be performed by properly-trained dermatologists and plastic surgeons. This risk is often reduced (but not eliminated) with the use of longer-wavelength lasers such as the 1064 nm Q-switched Nd:YAG device.
As mentioned previously, an additional advantage of long-wavelength lasers is the ability to penetrate more deeply into the skin as compared to shorter-wavelength lasers. This property becomes useful for the treatment of pigment located within the deeper layers of the dermis. However, the Nd:YAG may be less effective than shorter wavelength devices in targeting more superficial or diffuse pigment.
Another option for treating pigment lies within a tree fungus called Lignin peroxidase. This substance is an enzyme that has similar properties to melanin, but works by directly eliminating melanin pigment within the skin. This skin-lightening topical medication has shown to give more even skin pigmentation, while reducing dark spots. It is a novel new rapidly-acting remedy that has been shown to exert its effect in as little as one week of use. When utilized in combination with proper sun protection (SPF), this product provides an alternative approach to prescription skin-lightening agents on the market today.
Alternative Lightening Agents
The following topicals have been used solely or in combination with prescription lightening agents and have demonstrated effectiveness in reducing the severity of skin pigmentation.
- Ascorbic acid (Vitamin C)
- Kojic acid
If you or someone you know is concerned about skin pigmentation or uneven skin tone, make sure to schedule an appointment with a dermatologist. Many pigmented spot are benign, but sometimes it is very difficult to distinguish these benign skin lesions from abnormal moles and melanoma. For more information on what signs to look for, check out our article entitled “When Should I Get My Moles Checked?”.
- Arora P, Sarkar R, Garg VK, Arya L. Lasers for Treatment of Melasma and Post-Inflammatory Hyperpigmentation. Journal of Cutaneous and Aesthetic Surgery. 2012;5(2):93-103. doi:10.4103/0974-2077.99436.