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The vitiligo repigmentation patients hope for when working with their dermatology providers on different treatment options can vary significantly. Some patches of skin may start to regain pigment, while others are slower to respond, if they respond at all. Between individual patients, results can also vary widely. Researchers have observed that affected areas of the face and neck usually respond more effectively to vitiligo treatment efforts than the hands, feet, fingers, and toes. These uneven variations can be frustrating for patients, while posing questions for researchers. The current vitiligo clinical trial here at Apex Clinical Research Center is evaluating an investigational medication given by IV infusion to see whether it can bring color back to depigmented skin in patients with non-segmental vitiligo who have not found previous treatments to be successful. Repigmentation is therefore an important and relevant area of research. One of the central research questions surrounding vitiligo is: What determines whether and how successfully vitiligo repigmentation occurs?
What Has to Happen for Vitiligo Skin to Repigment?
The goal for vitiligo treatment is twofold. First, a treatment needs to slow or stop the body’s autoimmune attacks on melanocytes, the skin cells that create your skin pigment. Second, repigmentation depends on the skin’s ability to restore functioning melanocytes to depigmented areas so they can resume melanin production. As this happens, patches of colorless skin can start regaining their original pigmentation.
Interestingly, hair follicles serve as critical reservoirs for melanocyte stem cells, so researchers studying vitiligo repigmentation are interested in how these reservoirs can contribute to the development of mature melanocytes, which can then migrate into surrounding, depigmented skin and help restore color. In fact, many patients who see improvement in their pigmentation notice color returning around individual hairs before spreading outward.
So, the repigmentation that vitiligo researchers and patients are striving for depends on a gradual, biological process rather than a straightforward, immediate treatment response. The immune system needs to stop attacking melanocytes, and the skin needs to restore functioning melanocytes for repigmentation to occur.
Why Body Location Matters for Repigmentation
As dermatology research has revealed the connection between hair follicles and melanocyte production, the significant differences in how vitiligo treatments work on different patches of skin start to make more sense. Patients know from experience that treatment for vitiligo can produce varying degrees of repigmentation between different affected areas. While color may return more successfully to patches on the face and neck, vitiligo patches on the trunk and limbs may or may not respond as quickly, if at all. Those areas all have differing per-square-centimeter hair-follicle densities. This is both a general observation and an individual observation, as hair densities between patients can vary widely. Patches of skin with fewer hair follicles—hands, feet, fingertips, toes, lips, etc.—can be much harder to repigment. Hair-follicle density is one factor that may help explain why two areas of skin on the same patient can respond differently to vitiligo treatment.
What Else Can Affect Repigmentation Vitiligo Patients Experience?
Hair follicle density is only one of the factors that can affect how treatment for vitiligo works on different patches of skin. Vitiligo is a complex autoimmune condition with many factors determining its spread and how it responds to treatment. Ongoing dermatology research is trying to tease apart and understand how all the individual factors impact each other in order to find more effective vitiligo treatment options that produce better repigmentation results.
In addition to hair follicles acting as reservoirs for melanocyte stem cells, these other factors can also affect the repigmentation success of different vitiligo treatments:
- How long pigment loss has been present: The longer patches of skin have been without pigment, the longer it can take for them to experience repigmentation.
- Whether vitiligo is active or stable: Patients can go through periods of relative stability where patches don’t change shape or size very much. At other times, new patches may emerge and spread with surprising rapidity, even despite treatment.
- Extent of pigment loss: Larger areas of pigment loss can take much longer to repigment, even when a treatment is successful.
- Presence/absence of pigmented hairs in the area: Some vitiligo patients also experience pigment loss in the hairs emerging from certain hair follicles, indicating that the follicles themselves may have hampered melanocyte-production ability.
- Treatment type, duration, and consistency: Every patient is different, and individual variations in treatment for vitiligo also matter. For example, how long a patient has been using a particular treatment, or how consistently they’ve applied the treatment, can affect repigmentation results. Keep in mind, however, that even patients who have been extremely consistent in following their dermatology provider’s vitiligo treatment plan can experience variations as well.
- Individual differences in disease and immune activity: Vitiligo activity can be triggered by individual patient factors including stress, excessive sun exposure, hormonal activity, immune system activity, the Koebner phenomenon (where new vitiligo patches emerge at the site of cuts, abrasions, or scrapes), and co-existing autoimmune conditions.
Because all these factors can vary widely between patients, and even within individual patients themselves, ongoing vitiligo research is crucial for gaining a better understanding of the disease and how individual factors can affect how effective vitiligo treatments are. Researchers are working hard to understand why some patients respond more strongly than others, and how to develop vitiligo treatments that work better for more patients.
How Researchers Measure Repigmentation
As vitiligo clinical trials strive to discover better ways to help patients achieve repigmentation, researchers need standardized methods for determining repigmentation responses to treatment so they can gauge treatment effectiveness more objectively over time. Researchers use the Vitiligo Area Scoring Index (VASI) to measure the degree and extent of change in vitiligo macules. This helps them calculate an objective score to assess and monitor vitiligo progression and/or repigmentation improvement, so researchers can objectively measure the effectiveness of study drugs in clinical trials.
One important thing to know about VASI scores is that there are actually two different kinds: Facial VASI (F-VASI) and Total VASI (T-VASI). As we’ve established, vitiligo repigmentation treatment seems to work differently on different areas of the body, with the hair-follicle-rich face and neck skin often improving at faster rates than other areas of the body. Measuring facial and total-body response separately allows researchers to capture these differences in repigmentation more precisely. Vitiligo clinical trials may measure treatment benchmarks of 50%, 75%, or 90% improvement as clinically significant and promising.
Why Patient-Reported Repigmentation Matters
On the science side of dermatology research, objective scores like the two VASI scores are important, but patient-reported assessments are also critical to determine whether improvement is meaningful. Researchers aren’t just looking at whether pigment returns—they also want to know how this affects patients' lives with regard to how much pigment returns, where it returns, and how meaningful those changes are to the patients experiencing them. Patient experience and input are essential for finding better vitiligo treatment avenues.
What Repigmentation Can Teach Researchers About Vitiligo
Researchers continue to learn more about vitiligo biology and how it works, which can reveal better avenues for more successful vitiligo treatments. Differences in how patients respond and how macules develop and repigment provide key clues about:
- Melanocyte regeneration
- Immune activity
- The conditions necessary for pigment to return
- Why some patients and body areas respond better to treatment than others
As more dermatology research about vitiligo enhances our understanding of how the disease works and responds to treatments, we can identify more effective vitiligo treatment options that improve repigmentation outcomes for a wider variety of patients.
Advancing Vitiligo Treatment Through Clinical Trials
Many questions remain about why repigmentation varies so widely between patients, and even across different areas of the same patient’s skin. Vitiligo clinical trials can help researchers evaluate new investigational approaches to treatment while also expanding what we know about repigmentation, disease activity, safety, and treatment response.
Apex Clinical Research Center is currently conducting a clinical trial evaluating an investigational medication given by IV infusion to see whether it can bring color back to depigmented skin in patients with non-segmental vitiligo who have not found previous treatments to be successful.
If you have been diagnosed with vitiligo and are curious about clinical research, you have the opportunity to advance the science behind future vitiligo treatments. Participating in research can help us learn more about vitiligo and the potential for new approaches to treatment. Visit our “For Patients” page to learn more about participating in our dermatology clinical trials, and please contact us with any questions you have today.
