The saying that RF is "colorblind" and safe for all skin types is not entirely true. What is true is that it is not attracted to a color (chromophore) as lasers are. However, RF has the potential to heat up the superficial layer of skin, where the pigment cells (melanocytes) are found. If this layer is heated up too much, and there is prolonged inflammation, post inflammatory hyperpigmentation (PIH) can occur. The reason that Infini is generally safe for all skin types is that the insulated needles protect the upper part of the dermis from the heat in most cases. If the energy is high, the heat can spread upward, even with the insulation of the needles. Meticulous attention to placing the handpiece in a perpendicular position as well as at the proper depth is needed to keep the heat in the lower portion of the skin (the safe area). Turning down the energy a bit is an added safety precaution. Having said this, there are about half a dozen devices on the market with non insulated RF needles which are MUCH more likely to produce this problem. These devices still claim that RF is safe for all skin types which is misleading. From science alone, these devices will have a higher likelihood of producing PIH. As I have previously stated in other questions, devices are only as good as the operator. Most side effects from devices are related to user error. Either improper technique, wrong settings, or using on inappropriate patients. For PIH, hydroquinone, chemical peels, and possibly 1064 QS laser will help.
Dark patches after Infini
Thank you for the important question. Infini is safe for all skin types, but some thought must be put into how the treatment is delivered. For darker skin, the depth of the needles needs to be deeper in the skin. Superficial passes may result in inflammatory hyperpigmentation. In addition, the energy can be turned down to a lower setting for the first treatment, until the patient's response is known. Treating hyperpigmentation is much harder than avoiding it... but 8% hydroquinone is a good start. Take care and best of luck!
Skin darkening after Infini Treatment
Infini claims to be safe on all skin types;however I think that with darker skin tones energy settings need to kept lower and treatments kept a little deeper. The reason for this is that RF energies do create heat, so as long as that heat is deeper and a bit gentler, it should not impact surface pigment. To minimize that risk we now treat the skin with a supercold airflow device called the Zimmer. This helps protect that vulnerable surface layer from too much heat. Over time your skin should return to normal but it could take months.
Hyperpigmentation following Infini
The infini RF miconeedling device is an excellent device in all skin types. Even though hyperpigmentation is unlikely following this treatment, it could occur. No device is 100% in preventing this problem. I would see your doctor for correction of this problem. Generally, bleaching agents work very well.
Post Inflammatory Hyperpigmentation From Lasers -- Skin Lightening, Light Peels, microsecond YAG
Post inflammatory hyperpigmentation can be a result of strong energy treatments or an aggressive approach. Sometimes its a persons own skin type. I suggest seeing an expert for treatment. Best, Dr. Emer.