On a fateful afternoon six years ago, an elderly relative of mine who had recently suffered a stroke, laid motionless on the bed while his entire family — including doctors — presumed that he was not going to live. His dusky skin, though in a remarkably good condition for a nonagenarian, was turning deeper by the minute and he was gradually losing consciousness.
It so happened that a well-known and highly respected physician was visiting, and like a Caladrius at the bedside, immediately noticed the decline in the pulmonary status of my relative — betrayed only by his complexion. Thus, swift arrangements were made for the patient to be transported to the hospital, where he was accordingly treated and went on to live for another six months.
As it turns out, the deepening of his skin tone that everyone believed was a prelude to death, was in fact a clinical sign known as cyanosis — inexactly described by the mighty Harrison’s Principles of Internal Medicine as “a bluish colour of the skin and mucous membranes”, although it goes on to admit that, “the degree of cyanosis is modified by the colour of the cutaneous pigment and the thickness of the skin”.
Dark-skinned individuals may not turn conspicuously “blue” — and a seemingly trivial deviation from their normal complexion may point towards a life-threatening underlying pathology.
My first experience
This was my first experience, in a series of many, with the systemic nature of racial disparities in medical practice and literature. It took a professor of Internal Medicine to detect that a patient was in need of immediate care, which relied on him detecting an otherwise easily recognisable clinical phenomenon.
Were it not for his experience as a medical practitioner, my relative would probably be dead, and the fact that nobody was able to identify the cyanosis, not even some doctors, stands testament to the lack of diversity in medical teaching.
As such, medical literature is filled with images and words that describe clinical manifestations of diseases in terms of how they appear predominantly on light-skinned populations. The implications have been concerning but remain shockingly undocumented and unaddressed, despite involving just about every medical discipline.
From something as routine as identifying and treating skin pigmentations, to more concerning aspects of dermatological practice such as monitoring melanomas for danger signs, can become increasingly challenging for medical professionals who have not received proper training in the variability of disease presentation. Cases of domestic violence, non accidental injury and neglect may go unnoticed on melanin-rich skin.
Furthermore, the appearance of skin rashes among distinct racial groups is also markedly different. A noteworthy episode which I still remember from my final year as a medical student revolved around a Bengali child presenting with a dark, ominous rash that spread to major portions of her body.
Eventually, a diagnosis of Stevens-Johnson Syndrome (SJS) was made in time only after a senior physician examined him, noting how it slipped other junior doctors because of their familiarity with its blistering, pinkish-red textbook version.
In another instance, one of my professors corrected me when I answered ‘facial flushing’ on being quizzed about the signs of carbon dioxide retention, which, despite being relatively prominent in fair-skinned populations, may not be as evident in dark-skinned patients for whom ‘flapping tremors’ and ‘bounding pulses’ are more reliable clinical indicators.
Achieving health equity
Surprisingly, there exist limitations even from a technological standpoint to achieving health equity among different racial groups. The United States FDA has cautioned that pulse oximeters are less reliable for patients with darker skin, citing a report published in The New England Journal of Medicine, which found that “black patients had nearly three times the frequency of occult hypoxaemia that was not detected by pulse oximetry”. Mounting evidence suggests that racial and ethnic minority groups have been disproportionately affected by COVID-19.
Contrary to popular belief, “racial differences in skin colour are not caused by differences in the number of melanocytes”, according to the revised edition of Andrew’s Diseases of the Skin. Rather, “it is the number, size, and distribution of the melanosomes or pigment granules within keratinocytes that determine differences in skin colour.
Pale skin has fewer melanosomes, and these are smaller and packaged within membrane-bound complexes. Dark skin has more melanosomes, and these tend to be larger and singly dispersed”. Likewise, variations exist in human biology at a physiological, anatomical and biochemical level, that should be recognised and celebrated.
Decades of painstaking scientific research has traced the origin of modern humans to a single ancient population that lived in the wetlands of the African continent nearly 200,000 years ago. Our ancestors migrated out of the region in various directions, giving rise to an entire colour chart of human skin tones that we all can appreciate today.
With time, genetic and environmental factors have played an important role in the genesis of diseases that are unique in their epidemiology and clinical presentations to each racial group. Thus, in view of its ever-growing and profound if not inherent universality, medical science must evolve further by becoming inclusive of all races.
Dr Aamir Amin is a doctor who writes about current issues in Health and Clinical Practice including vaccines, drug addiction and the COVID-19 pandemic. As a medical student, he graduated summa cum laude from KYAMC, University of Rajshahi.