Skin Assessment in Wounds and Pressure Injuries in Persons With Dark Skin

Skin, the human body’s largest organ, is unique and complex, being continuously engaged in biochemical, bioregulatory, and bioprotective activities. Its major responsibilities include thermoregulation, sensory feedback from the external environment, immune function in combination with the lymphatic system, protection, and vitamin D synthesis. It is truly our suit of armor, protecting internal systems and structures from external exposures and threats.

Health care providers must thoroughly assess the skin beyond just visual inspection. We must use all our senses for comprehensive skin assessment. Such a thorough assessment is significantly more important in patients with darker skin tones because changes or signs of impending damage are more subtle.

The term “skin of color” identifies individuals of racial groups with skin darker than Caucasians and constitutes a wide range of racial and ethnic groups, including Africans, African Americans, African Caribbeans, Chinese, Japanese, Native American Navajo Indians, certain groups of fair-skinned persons (eg, Indians, Pakistanis, Arabs), and Hispanics.¹ Skin color is a blend of pigments resulting from skin chromophores: red (oxyhemoglobin), blue (deoxygenated  hemoglobin), yellow orange (carotene, an exogenous pigment), and brown (melanin).

Although thickness does not vary according to skin color, the stratum corneum of darker-pigmented people contains more layers of corneal cells. For this reason, the protective mantel is more compact and robust, although it contains fewer ceramides (essential lipids). Because of this, darker skin can sometimes appear ashy when it becomes dry. Ashiness describes the slate-gray appearance that the scales of the stratum corneum impart to the skin when superimposed on dark-colored skin.

Many issues related to dermatology and skin of color are present in the literature. Of note, systemic and institutional racism persist, cutaneous diseases are more often misdiagnosed in people of color, cutaneous diseases in people of color are understudied and have fewer treatment options, and there remains a lack of diversity among patients in clinical trials as well as a lack of diversity among dermatology professionals.² The levels of evidence are a challenge as well. For example, the following topic areas are supported by reasonable evidence and may contribute to higher itch levels in darker-toned individuals compared with those with lighter tones: higher transepidermal water loss (an indication of barrier function), lower ceramide levels in stratum corneum, lower pH in superficial stratum corneum, and larger mast cell granules. There is insufficient evidence to support the idea that darker-toned individuals have larger apocrine sweat glands and sebaceous glands, lower rates of sweating, and differences in microflora.^3,4

A study by Gunowa et al⁵ examined the evidence regarding pressure injuries in dark skin. Their search of the literature found 11 relevant articles where the foci of the research included the following: risk of sustaining a pressure injury based on skin tones, identification of pressure injuries among people with dark skin tones, pressure injuries and place of care, and socioeconomic impact on pressure injury development. Their findings indicate that people with darker skin tones are more likely to develop higher-stage pressure injuries. Reasons for this higher likelihood are not fully elucidated; however, it may be associated with current skin assessment protocols being less effective for people who have darker skin tones, resulting in early damage arising from pressure not being recognized.⁵

So, what does this mean? It means that visual inspection alone is not sufficient. Health care providers are “skin stewards,” and we must use all our senses when evaluating the skin, especially in patients with darker skin tones. To detect skin changes accurately in patients of all skin tones, visual assessment (ensured by proper lighting) must be followed by a thorough physical assessment of the problem area and its surrounding skin—a multi-modal approach. This includes palpating the skin and assessing for temperature and consistency changes. We must communicate with other health care providers, caregivers, and patients themselves when able to learn about skin issues. This includes thorough and objective documentation that transcends the continuum of care. We need to pay attention to the smell of the skin and wound, but only after bathing or cleansing, and must listen to the patient or caregivers because they will often tell us what is wrong if we actively listen and pay attention. Collectively, this provides a comprehensive approach to assessment.

Dark skin responds to trauma or inflammation by an increase or decrease in pigmentation called dyschromia. This is when the melanocytes respond in an exaggerated way. Dyschromia related to inflammation is referred to as post-inflammatory hyperpigmentation, where there is an increase in melanin production or uneven distribution. Looking for erythema or redness will not reveal evidence of an inflammatory process because darker skin tends to respond by a darkening of the natural skin tone. Hypopigmentation may also occur, represented by a localized or widespread loss of melanin in the skin. This may be due to loss of functional melanocytes and can lead to white/pink discoloration of the involved tissue, often described as depigmented macules and patches with feathered edges.⁶

There are factors to consider when assessing darkly pigmented skin.⁷ These include:

Skin color on intact dark skin remains unchanged and does not blanch

Localized skin color changes will occur at the site of pressure yet will differ from usual skin color

Tissue changes from damage/devitalization will make the skin feel cool to the touch; this may be preceded by localized heat from an inflammatory response

A previous full-thickness pressure injury/ulcer site will remain lighter in color until full scar resolution

Erythema in darker skin may appear purplish/bluish or violaceous (eggplant color)

Induration/non-pitting edema >15 mm in diameter may occur with shiny/taut skin

Persons may or may not report pain or itching at the site of tissue devitalization

In summary, skin assessment requires vigilance and close attention utilizing all our senses. This is of utmost importance in persons with darker skin tones as subtle telltale changes are often missed. Moreover, risk assessment tools designed for people with darker skin tones are needed as well as more research focused on patients with skin of color both in dermatology and wound management. Lastly, health care providers should invest in dermatology texts specific to skin of color to assist in clinical practice. A good starting point is the free e-book, Mind the Gap: A Handbook of Clinical Signs in Black and Brown Skin, available at https://www.blackandbrownskin.co.uk/mindthegap. 

REFERENCES

1. Taylor SC, Kyei A. Defining Skin of Color. In: Kelly A, Taylor SC, Lim HW, Serrano A. eds. Taylor and Kelly’s Dermatology for Skin of Color, 2e. McGraw Hill; 2016. Accessed September 14, 2022. https://accessmedicine.mhmedical.com/content.aspx?bookid=2585&sectionid=211763356

2. Skin of Color Society (SOCS). Learn more about SOCS.  https://skinofcolorsociety.org/about-socs/

3. Wesley NO, Maibach HI. Racial (ethnic) differences in skin properties: the objective data. Am J Clin Dermatol. 2003;4(12):843-860. doi:10.2165/00128071-200304120-00004

4. McColl M, Boozalis E, Aguh C, Eseonu AC,  Okoye GA, Kwatra SG. Pruritus in Black skin: unique molecular characteristics and clinical features. J Natl Med Assoc. 2021;113(1):30-38. doi:10.1016/j.jnma.2020.07.002

5. Gunowa N, Hutchinson M, Brooke J, Jackson D. Pressure injuries in people with darker skin tones: a literature review. J Clin Nurs. 2018;27:3266-3275. doi:10.1111/jocn.14062

6. Grimes PE. Management of hyperpigmentation in darker racial ethnic groups. Semin Cutan Med Surg. 2009;28(2):77-85. doi:10.1016/j.sder.2009.04.001

7. Bennett AM. Report of the task force on the implications for darkly pigmented intact skin in the prediction and prevention of pressure ulcers. Adv Wound Care. 1995;8(6):34-35.

Dr Hettrick is a Professor, Department of Physical Therapy, Nova Southeastern University, Fort Lauderdale, FL.
The opinions and statements expressed herein are specific to the respective author and not necessarily those of Wound Management & Prevention
or HMP Global. This article was not subject to the Wound Management & Prevention peer-review process.