Residency · Residency · Dermatology

Skin of Color Dermatology

Introduction

Skin of color (SOC) encompasses individuals of African, Asian, Hispanic/Latino, Native American, Pacific Islander, and Middle Eastern descent, representing the global majority. Dermatologic disease can present differently in richly pigmented skin, and certain conditions are more prevalent or carry unique considerations in these populations. Training gaps in SOC dermatology contribute to diagnostic delays and health disparities. This lecture addresses the structural, physiologic, and clinical differences essential for equitable dermatologic care.

Structural and Physiologic Differences

Melanin and Melanosomes

Melanin content is the primary determinant of skin color, though all skin types have similar melanocyte density of approximately 1,000 to 2,000 per square millimeter. Darker skin has larger, individually dispersed melanosomes, in contrast to the smaller, aggregated melanosomes in lighter skin. These melanosomes persist throughout the stratum corneum in darker skin, whereas they are degraded earlier in lighter skin. Melanin provides inherent photoprotection with an SPF equivalent of approximately 13 in darkly pigmented skin versus 3 in fair skin. Despite this photoprotection, skin cancer does occur in SOC patients and is more likely to be diagnosed at advanced stages.

Stratum Corneum

The stratum corneum in darker skin has an increased number of cell layers and greater intracellular cohesion. Higher transepidermal water loss has been reported in some studies, though this remains debated. Greater skin surface lipid content and ceramide composition variations also exist.

Fibroblasts

Higher fibroblast density and more active fibroblasts characterize darker skin, along with increased collagen fiber density and a greater proportion of larger collagen fiber bundles. These properties contribute to the greater susceptibility to keloid and hypertrophic scar formation.

Photoaging Differences

Signs of photoaging appear 10 to 20 years later in darker skin compared to lighter skin. When photoaging does occur, it presents primarily as dyschromia and textural changes rather than fine wrinkles. Dermatoheliosis and solar elastosis are less pronounced.

Pigmentary Disorders in Skin of Color

Post-Inflammatory Hyperpigmentation (PIH)

PIH is the most common pigmentary concern in SOC patients, resulting from increased melanin production and transfer following any inflammatory insult such as acne, eczema, trauma, or procedures. It may persist for months to years, and the psychosocial impact is significant. Epidermal melanin produces a brown color and responds to topical therapy including hydroquinone, retinoids, azelaic acid, vitamin C, and kojic acid. Dermal melanin produces a blue-gray color from melanin within dermal macrophages and is more recalcitrant, often resulting from more severe inflammation. Treatment includes hydroquinone 4% (the gold standard, limited to 4 to 6 months to avoid ochronosis), triple combination therapy (hydroquinone plus tretinoin plus fluocinolone), azelaic acid 15 to 20%, tranexamic acid (oral or topical), and superficial chemical peels only, as deep peels are contraindicated.

Post-Inflammatory Hypopigmentation

Loss of melanin following inflammation is usually temporary because melanocytes are preserved. It commonly occurs after cryotherapy, dermabrasion, laser therapy, or inflammatory dermatoses. Self-resolution over months is typical, and topical tacrolimus or low-potency corticosteroids can reduce background inflammation.

Melasma

Melasma disproportionately affects SOC patients with Fitzpatrick types III through VI. It is hormonally driven by pregnancy, oral contraceptives, and hormone replacement therapy. Mixed epidermal and dermal melanin is common, making treatment challenging. Sun protection is paramount, with hydroquinone, retinoids, and azelaic acid as topical agents, and aggressive procedures should be avoided. Tranexamic acid, given orally at 250 mg twice daily or topically at 5%, has emerging evidence for efficacy.

Dermatosis Papulosa Nigra

These multiple small, brown-black pedunculated papules on the face and neck are histologically identical to seborrheic keratoses, affecting up to 35% of Black individuals and more common in women. Treatment, if desired, involves light electrodesiccation or scissor excision, with care to avoid aggressive treatment that risks PIH or scarring.

<image>Clinical photograph comparison showing common pigmentary conditions in skin of color: post-inflammatory hyperpigmentation following acne on the cheeks, melasma in a malar distribution, dermatosis papulosa nigra on the face, and post-inflammatory hypopigmentation from resolved eczema</image>

Conditions with Distinct Presentations in Skin of Color

Acne Vulgaris

In SOC patients, inflammatory lesions and PIH are often more distressing than the acne itself. Pomade acne produces comedonal acne on the forehead from hair care products. Acne keloidalis nuchae presents as follicular papules and keloid-like plaques on the posterior scalp and nape, common in Black men. Treatment considerations include early aggressive treatment to minimize PIH, retinoids to reduce PIH, and avoidance of excessive benzoyl peroxide concentrations that can cause irritation and hypopigmentation.

Eczema and Atopic Dermatitis

Prevalence is higher in Black children (19.3%) compared to White children (16.1%). Follicular eczema presents as perifollicular papules rather than classic eczematous patches and may be misdiagnosed. Papular eczema produces discrete papules rather than confluent plaques. Lichenification is more prominent, with prurigo nodularis as a complication. Erythema may appear violaceous or hyperpigmented rather than red, making visual assessment more difficult.

Psoriasis

Psoriasis in SOC may appear violaceous, gray, or hyperpigmented rather than salmon-pink, and silvery scale may be less apparent or appear gray-brown. PIH and hypopigmentation from resolved plaques are major concerns. Scalp psoriasis is common and may be mistaken for seborrheic dermatitis or traction changes. NB-UVB is generally safe, and topical vitamin D analogues and corticosteroids are first-line.

Hair Disorders

Central centrifugal cicatricial alopecia (CCCA) is the most common scarring alopecia in Black women, producing progressive hair loss beginning at the vertex and crown, associated with hair care practices and PADI3 mutations. Traction alopecia results from tight hairstyles and is reversible if caught early. Pseudofolliculitis barbae affects up to 80% of Black men, and treatment includes avoiding close shaving, chemical depilatories, topical retinoids, eflornithine, and laser hair removal with the Nd:YAG 1064 nm laser being safest.

Procedural Considerations in Skin of Color

The Nd:YAG 1064 nm is the safest laser for hair removal and vascular lesions in darker skin, while Q-switched ruby and alexandrite lasers should be avoided for pigmented lesions in dark skin types. Only superficial chemical peels should be used in skin types IV through VI. Higher risk of keloid formation necessitates discussion of prophylaxis before any elective procedure.

<image>Diagram showing the Fitzpatrick skin phototype classification (types I-VI) with corresponding characteristics, along with a safety profile chart indicating relative risk levels for various dermatologic procedures (laser, chemical peel, cryotherapy) across skin types</image>

Skin Cancer in Skin of Color

Overall incidence is lower but morbidity and mortality are higher due to delayed diagnosis. SCC is the most common skin cancer in Black patients, often arising in non-sun-exposed areas. Melanoma in SOC is predominantly the acral lentiginous subtype, and subungual melanoma must be distinguished from benign longitudinal melanonychia. Dermatofibrosarcoma protuberans has a higher incidence in Black patients.

Clinical Pearls

Erythema in darker skin may present as violaceous, brown, or simply darkened skin, making palpation for warmth and induration essential. PIH is often more distressing than the primary dermatosis, and treatment plans should address both. CCCA should be considered in any Black woman with progressive vertex hair loss, and early biopsy prevents irreversible scarring alopecia. For laser procedures in skin of color, the Nd:YAG 1064 nm is the safest choice with test spots always performed. Acral sites require special attention for melanoma screening in SOC patients.

References

1. Alexis AF, Sergay AB, Taylor SC. Common dermatologic disorders in skin of color: a comparative practice survey. Cutis. 2007;80(5):387-394.
2. Davis EC, Callender VD. Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. J Clin Aesthet Dermatol. 2010;3(7):20-31.
3. Dlova NC, Salkey KS, Callender VD, McMichael AJ. Central centrifugal cicatricial alopecia: new insights and a call for action. J Investig Dermatol Symp Proc. 2017;18(2):S54-S56.
4. Agbai ON, Buster K, Sanchez M, et al. Skin cancer and photoprotection in people of color: a review and recommendations for physicians and the public. J Am Acad Dermatol. 2014;70(4):748-762.

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