The Vital Role of Skin Color
August 10, 2020
Since we all have unique qualities, it is not surprising that human skin comes in a wide variety of colors that can range from a very pale white to very dark brown or black, as well as numerous shades in between. Melanocytes are found in the epidermal skin cells and make up melanin pigment, which is responsible for skin color. However, the number of melanocytes is the same for all races regardless of skin color. So, whether your skin color classification is fair, olive, or brown, the number of melanocytes found in the basal layer of the skin is EQUAL. Tanning, on the other hand, relates to the amount of melanin pigment produced and can be increased by increasing exposure to sunlight (UV light). This explains why people with albinism, who are unable to make melanin pigment, appear to be void of color. Albinos live with an increased risk of sunburn and skin cancer, as the pigment that protects skin from UV rays is not present in a sufficient amount. If you have albinism, you should wear sunscreen with a high sun-protection factor (SPF).
Brief History of Skin Color Classification
Prior to the mid-1970s, doctors and researchers often struggled to accurately determine what would be a safe dose of exposure to ultraviolet (UV) light in assessing an individual’s risk of premature aging and skin cancer. That’s when the skin typing scale was created by American dermatologist, Thomas B. Fitzpatrick, MD, PhD. As Chairman of Dermatology at Harvard Medical School and Chief of the Massachusetts General Hospital Dermatology Service for nearly three decades, Dr. Fitzpatrick focused on defining a numerical scale to use for photo-typing human skin color. His skin phototype scale measured a constitutional color, which is amount of pigment present in a person’s skin at birth. In addition to understanding traits like hair, skin, and eye color, skin phototypes can be used in dermatology to estimate tolerable dosages of UV light, phototherapy, and laser light for the treatment of skin conditions, such as psoriasis or cancer.
In the early 1960s, Dr. Fitzpatrick had a specific interest in the basic biology of the malignant melanocyte found in skin tumors. At that time, very little was known about melanoma, which was and still is today the deadliest form of skin cancer. Prior to his entrance into the field, melanoma often was not diagnosed until it was too late for the patient to experience a full recovery from the disease. Almost a dozen years prior to the Fitzpatrick Scale, he and Dr. Wallace H. Clark, Jr. collaborated on pigmented lesions and included the earliest descriptions of the clinical features of melanoma in the book Tumors of the Skin (Fitzpatrick and Clark, 1963). As founding members of the first pigmented lesion clinic (PLC) in the United States, Doctors Fitzpatrick and Clark joined forces with Dr. John Raker and Dr. Martin C. Mihm, Jr. to study the unique diagnostic features of melanoma.
With funding from President Richard Nixon’s “War on Cancer”, the PLC expanded in the early 70s and the Melanoma Clinical Cooperative Group, which recruited many universities, sought to explain the clinical and prognostic factors associated with cutaneous melanoma. It was the first coordinated study funded by the National Institute of Health (NIH) for studying a single type of cancer. As the PLC became a worldwide model for a multidisciplinary approach to managing cases of melanoma, many doctors expressed a special interest in the role that sunlight played in the etiology of malignant melanoma. Fitzpatrick’s work, as to how melanin pigment that is responsible for determining hair, eye, and skin color is affected by exposure to UV radiation, led to a broader understanding among medical researchers as to why darker skin burns less and tans more easily.
Understanding the Importance of Skin Color
Although people with photosensitivity to sunlight may burn faster due a medical condition, disease, or medication they are taking, the ability of their skin to tan is not influenced by photosensitivity. The skin phototype classification system is based solely on the ability of a given color of skin to tan as well as its sensitivity to burn when exposed to ultraviolet radiation. Although melanin pigment plays a crucial role in protecting skin from the sun’s harmful rays, too much pigmentation can limit the natural absorption of UV light for vitamin D synthesis. In general, the broad range of skin colors around the world developed as such due to the intensity of the sunlight of each population’s specific ancestral environment. Eumelanin (black or brown in color) and pheomelanin (red or yellow in color) are the two types of melanin pigmentation.
Currently, the Fitzpatrick Scale, which is commonly used in the assessment of skin cancer risk, has six (6) skin type classifications that range from extremely fair (Type I) to very dark (Type VI). Dermatologist also use traits such as hair and eye color to determine a more exact phototype. Recognized skin phototypes include:
- Type I – Ivory white in color, burns easily, and never tans
- Type II – White in color, burns easily, and tans minimally but with difficulty
- Type III – White in color, burns moderately, and tans moderately
- Type IV – Beige or olive, burns minimally, and tans moderately and easily
- Type V – Moderately brown in color, rarely burns, and tans profusely
- Type VI – Dark brown to black in color, never burns, and tans profusely
Although renderings of the Fitzpatrick Scale can be used by the general population for self-assessment of sun sensitivity, skin phototyping can be measured objectively with special instruments for skin tone analysis. In addition to predetermining UV sensitivity, phototypes are useful in identifying potential complications for dermatologic procedures like laser resurfacing.
Science Beyond Skin Photo Types
Dr. Fitzpatrick arrived on the medical scene when the etiology of malignant melanoma tumors was unclear, but his personal contributions and those of his understudies definitely furthered the understanding of how UV exposure could be used as a predictive factor in determining patient outcomes. Knowing your skin type can help you make better decisions about skincare. Moreover, all skin colors can benefit from covering up, seeking shade, and using sunscreen for UV protection as well as its anti-aging properties. Recent studies have suggested melanin is not the only factor that determines UV sensitivity. For example, people who suffer from a disease called vitiligo, where their skin becomes depigmented in some areas, do not appear to have higher incidence rates of melanoma in affected areas.
There is evidence that the chemical intermediates of melanin synthesis pathways may contribute to protection beyond what the Fitzpatrick Scale would indicate for the depigmented areas of lighter skin. After participating in a study hosted by Ranjan Perera, Ph.D., the scientific director of Analytical Genomics and Bioinformatics at Sanford Burnham Prebys, Michael Steppie, M.D., a clinical professor of Dermatology at Florida State University College of Medicine and the President and Medical Director of Associates in Dermatology, may have identified a hidden culprit called miR-211 that is not found in vitiligo cells. In a study published in the Journal of Investigative Dermatology, it was reported that the microRNA may prevent gene expression by turning off genes linked to mitochondria creation. These biomarkers could potentially provide earlier and more reliable clinical diagnostics for melanoma.
Protecting Your Skin Color from Skin Cancer
Melanoma is the deadliest form of all skin cancers and causes more than 75% of skin cancer deaths. However, when caught early, melanoma is almost always curable. As a noted Florida dermatologist and long-time advocate of skin cancer prevention, Dr. Steppie offers these sun safety tips* for all people who live in warm regions, and especially in the Central Florida communities of the Sunshine State:
- Remember that all skin types can develop skin cancer including people who tan easily as well as those who have naturally dark skin.
- Generously apply sunscreen to all exposed skin — even on cloudy days — year-round.
- Use a sunscreen that provides broad-spectrum protection from both UVA and UVB rays and has a sun protection factor (SPF) of at least 30 SPF.
- Apply approximately one ounce of sunscreen (a shot-glassful) 15 minutes before sun exposure.
- Reapply sunscreen every two hours and after swimming or sweating.
- Keep newborns out of the sun. Sunscreens should be used on babies over the age of six months.
- Wear a long-sleeved shirt, pants, a wide-brimmed hat (preferably sun-protective clothing, accessories and swimwear carrying a UPF 50+ label) and UV-Blocking sunglasses.
- Seek shade when possible. The sun’s rays are the strongest between 10 a.m. and 4 p.m.
- Water, snow, and sand reflect and magnify the damaging rays of the sun, increasing your chance of sunburn. Especially during peak hours while at the beach, stay in the shade from an umbrella carrying a UPF 50+.
- Avoid tanning beds – there is no way to get a tan through UV exposure without increasing the risk for skin cancer. Using a tanning bed before age 35 increases your risk for melanoma by 75 percent.
- Be aware that certain prescription medications and over-the-counter drugs can increase your skin’s sensitivity to sunlight
- Sun-proof your car windows with UVA-filtering window glass or film.
The typical melanoma skin lesion is a dark mole and patients should self-check for changes in the number, size, shape and color of pigmented areas. Most patients do not feel any symptoms of skin cancer but may notice a new or changing spot, or a sore that will not heal. However, advanced stages of melanoma, as well as squamous cell carcinoma that has spread into the bloodstream, may cause associated symptoms, such as pain in an area close to the mole or skin lesion. Skin cancer is the most common cancer in the United States, with millions of cases diagnosed each year. It’s also one of the most preventable cancers and highly treatable when diagnosed early. The Fitzpatrick system of classifying skin color by phototype is still commonly used in the assessment of skin cancer risk today.
NOTE: Although people with skin Type I and Type II are at the highest risk for developing skin cancer, the Skin Cancer Foundation warns that melanoma in darker skin types is often diagnosed at a later stage, which often contributes to poorer patient outcomes. Among darker-skinned people, including African Americans, Hispanics and Asian Americans, melanoma (acral lentiginous melanoma) can develop on parts of the body that are not often exposed to the sun. So, all skin types should have an annual skin checkup with a dermatologist.