“Dark skin” generally refers to skin classified as Fitzpatrick type IV, V, or VI, meaning it contains high levels of the brown-black pigment eumelanin and rarely or never sunburns. There’s no single universal cutoff, but dermatology uses several classification systems that draw lines between lighter and darker skin tones based on how skin responds to sunlight, how much pigment it contains, and how it appears under measurement tools.
How Skin Color Is Classified
The most widely used system is the Fitzpatrick scale, developed in the 1970s and expanded in 1988 to include darker skin tones. It sorts skin into six types based on how easily it burns and how readily it tans. Types I through III cover lighter skin that burns easily and tans minimally to moderately. Types IV through VI describe progressively darker skin that rarely burns and tans deeply or is deeply pigmented year-round. People with African, South Asian, Middle Eastern, Southeast Asian, Hispanic, Pacific Islander, and Indigenous heritage commonly fall into the IV to VI range, though people of mixed heritage often self-report across several categories.
A more objective measurement is the Individual Typology Angle (ITA), which uses a device called a colorimeter to assign a numerical degree value to skin color. Under this system, skin is classified across six groups from “very light” (above 55°) down to “dark” (below negative 30°). “Brown” skin falls between negative 30° and 10°, while “dark” is anything below negative 30°. Unlike the Fitzpatrick scale, ITA doesn’t rely on self-reporting or sun-response questions, making it more consistent across populations.
More recently, the Monk Skin Tone Scale was developed as a 10-shade system designed to be more inclusive, particularly for technology applications like facial recognition and AI-based dermatology tools. Its finer gradations aim to capture the wide range of tones within communities that older scales lumped together.
What Makes Skin Dark
Skin color comes down to melanin, a pigment produced by specialized cells called melanocytes. Everyone has roughly the same number of melanocytes regardless of skin color. The difference lies in how much melanin those cells produce, what type of melanin dominates, and how the pigment packages (called melanosomes) are distributed throughout the skin’s outer layer.
There are two main forms of melanin. Eumelanin is the brown-black variety, and pheomelanin is yellow-red. Darker skin has a much higher ratio of eumelanin to pheomelanin, driven by higher activity of a key enzyme involved in melanin production and lower availability of the amino acid cysteine. When that enzyme is highly active and cysteine is low, cells produce eumelanin almost exclusively. In lighter skin, lower enzyme activity and more cysteine shift the balance toward pheomelanin, which is associated with increased sun sensitivity, freckling, and less tanning ability.
Darker skin also has larger melanosomes that are distributed individually throughout skin cells rather than clustered in small groups. This arrangement provides more even, dense pigmentation and more effective absorption of ultraviolet radiation.
Built-In Sun Protection and Vitamin D Trade-Offs
The high eumelanin content in dark skin acts as a natural sunscreen. Black skin has an estimated natural SPF of about 13.4, nearly four times greater than white skin. This means dark skin filters out significantly more UV radiation before it can damage DNA in deeper skin layers, which is why sunburn is rare in Fitzpatrick types V and VI.
The trade-off is vitamin D production. UV-B rays trigger the skin to convert a cholesterol precursor into vitamin D, and melanin slows that process by absorbing those same rays. In one study, lighter skin converted about 3% of this precursor into pre-vitamin D after 30 minutes of sun exposure, while darker skin converted just 0.3% in the same time. Practically, someone with lighter skin can generate adequate vitamin D from about 30 minutes of daily sun, while someone with very dark skin may need upward of two hours of exposure to produce the same amount. This is one reason vitamin D deficiency is more common in people with dark skin, especially those living at higher latitudes with less intense sunlight.
How Skin Conditions Look Different on Dark Skin
Many common skin conditions were originally described and photographed on lighter skin, and their textbook appearance doesn’t always match what happens on darker skin. Redness, for instance, is a hallmark of inflammation in conditions like eczema, psoriasis, rosacea, and lupus. On light skin, these show up as bright red patches that are easy to spot. On dark skin, that same inflammation often appears violaceous (purplish), gray, or dark brown instead. The redness is still happening underneath, caused by the same blood vessel dilation, but the higher concentration of melanin in the outer skin layers masks the typical red color.
This visual difference has real consequences. Clinicians trained to look for redness as the primary sign of inflammation can miss or underestimate conditions in darker-skinned patients. Psoriasis may look like violaceous-brown plaques where scaling is more prominent than color change. A drug reaction may present as dusky or hyperpigmented patches rather than the diffuse redness seen on lighter skin. Even blanching, the test where pressing on skin briefly turns it white, is less visible in darker tones.
Post-Inflammatory Hyperpigmentation
One of the most common skin concerns for people with dark skin is post-inflammatory hyperpigmentation, or PIH. This is the dark discoloration left behind after any kind of skin injury or inflammation, from acne and eczema to cuts, burns, or cosmetic procedures. It affects all skin types but is significantly more frequent and more severe in Fitzpatrick types III through VI. Population studies have documented acne-related PIH in roughly 47 to 65% of African American, Hispanic, and Asian patients.
The mechanism is straightforward: inflammation damages the base layer of the skin, triggering melanocytes to release extra melanin into surrounding cells. Inflammatory signaling molecules and reactive oxygen species ramp up melanin production and transport, and the resulting pigment granules can persist for weeks to months. In darker skin, this response is amplified. Research has found that healthy African American skin already expresses higher levels of certain pro-inflammatory genes compared to European skin, which may partially explain the stronger pigmentation response to even minor injuries.
PIH is not dangerous, but it can be more visually distressing than the original condition that caused it, and it often takes longer to fade in darker skin. This is why dermatologists treating patients with dark skin often prioritize preventing PIH alongside treating the underlying condition.
Skin Cancer Risks in Dark Skin
Dark skin’s natural UV protection does lower overall skin cancer rates significantly, but it doesn’t eliminate the risk. The most notable concern is acral lentiginous melanoma, a rare subtype that appears on the palms, soles of the feet, and under the nails. These are areas with less pigmentation regardless of overall skin tone, and this type of melanoma is not linked to UV exposure. While acral lentiginous melanoma accounts for only 2 to 3% of all melanoma cases in Western countries, it represents 55 to 65% of melanomas diagnosed in people of color.
Because skin cancer awareness campaigns have traditionally focused on sun-exposed moles and fair-skinned populations, both patients and doctors may not think to check these non-sun-exposed areas. Late detection is a major reason why melanoma outcomes tend to be worse in people with dark skin, not because the cancer itself is more aggressive, but because it’s found at a more advanced stage.
Scarring Differences
Dark skin is also more prone to excess scarring. Keloid scars, which are raised, firm scars that grow beyond the boundaries of the original wound, and hypertrophic scars occur more frequently in darkly pigmented skin. The mechanism appears to involve sustained interactions between overactive melanocytes near damaged skin and cells in the deeper tissue layers, triggering inflammatory signaling pathways that promote excessive scar tissue formation. This tendency is important to factor into decisions about elective procedures, piercings, or surgical approaches.